# Installing the First AFS Machine

This chapter describes how to install the first AFS machine in your cell, configuring it as both a file server machine and a client machine. After completing all procedures in this chapter, you can remove the client functionality if you wish, as described in Removing Client Functionality.

To install additional file server machines after completing this chapter, see Installing Additional Server Machines.

To install additional client machines after completing this chapter, see Installing Additional Client Machines.

## Requirements and Configuration Decisions

The instructions in this chapter assume that you meet the following requirements.

- You are logged onto the machine's console as the local superuser root

- A standard version of one of the operating systems supported by the current version of AFS is running on the machine

- You have either installed the provided OpenAFS packages for your system, have access to a binary distribution tarball, or have successfully built OpenAFS from source

- You have a Kerberos v5 realm running for your site. If you are working with an existing cell which uses legacy kaserver or Kerberos v4 for authentication, please see kaserver and Legacy Kerberos v4 Authentication for the modifications required to this installation procedure.

- You have NTP or a similar time service deployed to ensure rough clock syncronistation between your clients and servers.

You must make the following configuration decisions while installing the first AFS machine. To speed the installation itself, it is best to make the decisions before beginning. See the chapter in the OpenAFS Administration Guide about issues in cell administration and configuration for detailed guidelines.

- Select the first AFS machine

- Select the cell name

- Decide which partitions or logical volumes to configure as AFS server partitions, and choose the directory names on which to mount them

- Decide how big to make the client cache

- Decide how to configure the top levels of your cell's AFS filespace

This chapter is divided into three large sections corresponding to the three parts of installing the first AFS machine. Perform all of the steps in the order they appear. Each functional section begins with a summary of the procedures to perform. The sections are as follows:

- Installing server functionality (begins in Overview: Installing Server Functionality)

- Installing client functionality (begins in Overview: Installing Client Functionality)

- Configuring your cell's filespace, establishing further security mechanisms, and enabling access to foreign cells (begins in Overview: Completing the Installation of the First AFS Machine)

## Overview: Installing Server Functionality

In the first phase of installing your cell's first AFS machine, you install file server and database server functionality by performing the following procedures:

1. Choose which machine to install as the first AFS machine

2. Create AFS-related directories on the local disk

3. Incorporate AFS modifications into the machine's kernel

4. Configure partitions or logical volumes for storing AFS volumes

5. On some system types (very rare), install and configure an AFS-modified version of the fsck program

6. If the machine is to remain a client machine, incorporate AFS into its authentication system

7. Start the Basic OverSeer (BOS) Server

8. Define the cell name and the machine's cell membership

9. Start the database server processes: Backup Server, Protection Server, and Volume Location (VL) Server

10. Configure initial security mechanisms

11. Start the fs process, which incorporates three component processes: the File Server, Volume Server, and Salvager

12. Optionally, start the server portion of the Update Server

## Choosing the First AFS Machine

The first AFS machine you install must have sufficient disk space to store AFS volumes. When you later install additional file server machines in your cell, you can distribute these volumes among the different machines as you see fit.

These instructions configure the first AFS machine as a database server machine, and optionally as the binary distribution machine for its system type and the cell's system control machine. For a description of these roles, see the OpenAFS Administration Guide.

Installation of additional machines is simplest if the first machine has the lowest IP address of any database server machine you currently plan to install. If you later install database server functionality on a machine with a lower IP address, you must first update the /usr/vice/etc/CellServDB file on all of your cell's client machines. For more details, see Installing Database Server Functionality.

## Creating AFS Directories

If you are installing from packages (such as Debian .deb or Fedora/SuSe .rpm files), you should now install all of the available OpenAFS packages for your system type. Typically, these will include packages for client and server functionality, and a seperate package containing a suitable kernel module for your running kernel. Consult the package lists on the OpenAFS website to determine the packages appropriate for your system. The preparer of such packages may have included some helper scripts to partially automate the creation of a new cell; such scripts can supersede much of the procedures described in the rest of this document.

If you are installing from a tarfile, or from a locally compiled source tree you should create the /usr/afs and /usr/vice/etc directories on the local disk, to house server and client files respectively. Subsequent instructions copy files from the distribution tarfile into them.

       # mkdir /usr/afs
       # mkdir /usr/vice
       # mkdir /usr/vice/etc

## Performing Platform-Specific Procedures

Several of the initial procedures for installing a file server machine differ for each system type. For convenience, the following sections group them together for each system type:

- Incorporate AFS modifications into the kernel.

  The kernel on every AFS client machine and, on some systems, the AFS fileservers, must incorporate AFS extensions. On machines that use a dynamic kernel module loader, it is conventional to alter the machine's initialization script to load the AFS extensions at each reboot. The preparer of OS-format binary packages may have included an init script which automates the loading of the needed kernel module, eliminating a need to manually configure this step.

- Configure server partitions or logical volumes to house AFS volumes.

  Every AFS file server machine should have at least one partition or logical volume dedicated to storing AFS volumes (for convenience, the documentation hereafter refers to partitions only). Each server partition is mounted at a directory named /vicep xx, where xx is one or two lowercase letters. By convention, the first 26 partitions are mounted on the directories called /vicepa through /vicepz, the 27th one is mounted on the /vicepaa directory, and so on through /vicepaz and /vicepba, continuing up to the index corresponding to the maximum number of server partitions supported in the current version of AFS (which is specified in the OpenAFS Release Notes).

  The /vicep xx directories must reside in the file server machine's root directory, not in one of its subdirectories (for example, /usr/vicepa is not an acceptable directory location).

  The fileserver will refuse to mount any /vicep xx folders that are not separate partitions without additional configuration.

  The separate partition requirement may be overridden by creating a file named /vicepxx/AlwaysAttach; however, mixed-use partitions, whether cache or fileserver, have the risk that a non-AFS use will fill the partition and not leave enough free space for AFS. Even though it is allowed, be wary of configuring a mixed-use partition without understanding the ramifications of doing so with the workload on your filesystem.

  You can also add or remove server partitions on an existing file server machine. For instructions, see the chapter in the OpenAFS Administration Guide about maintaining server machines.

  Not all file system types supported by an operating system are necessarily supported as AFS server partitions. For possible restrictions, see the OpenAFS Release Notes.

- On (rare) system types using the inode storage format, install and configure a modified fsck program which recognizes the structures that the File Server uses to organize volume data on AFS server partitions. The fsck program provided with the operating system does not understand the AFS data structures, and so removes them to the lost+found directory.

- If the machine is to remain an AFS client machine, modify the machine's authentication system so that users obtain an AFS token as they log into the local file system. Using AFS is simpler and more convenient for your users if you make the modifications on all client machines. Otherwise, users must perform a two or three step login procedure (login to the local system, then obtain Kerberos credentials, and then issue the aklog command). For further discussion of AFS authentication, see the chapter in the OpenAFS Administration Guide about cell configuration and administration issues.

To continue, proceed to the appropriate section:

- Getting Started on Linux Systems

- Getting Started on Solaris Systems

## Getting Started on Linux Systems

Since this guide was originally written, the procedure for starting OpenAFS has diverged significantly between different Linux distributions. The instructions that follow are appropriate for both the Fedora and RedHat Enterprise Linux packages distributed by OpenAFS. Additional instructions are provided for those building from source.

Begin by running the AFS client startup scripts, which call the modprobe program to dynamically load the AFS modifications into the kernel. Then create partitions for storing AFS volumes. You do not need to replace the Linux fsck program. If the machine is to remain an AFS client machine, incorporate AFS into the machine's Pluggable Authentication Module (PAM) scheme.

### Loading AFS into the Linux Kernel

The modprobe program is the dynamic kernel loader for Linux. Linux does not support incorporation of AFS modifications during a kernel build.

For AFS to function correctly, the modprobe program must run each time the machine reboots, so your distribution's AFS initialization script invokes it automatically. The script also includes commands that select the appropriate AFS library file automatically. In this section you run the script.

In later sections you verify that the script correctly initializes all AFS components, then activate a configuration variable, which results in the script being incorporated into the Linux startup and shutdown sequence.

The procedure for starting up OpenAFS depends upon your distribution

#### Fedora and RedHat Enterprise Linux

OpenAFS provides RPMS for all current Fedora and RedHat Enterprise Linux (RHEL) releases prior to EL7 on the OpenAFS web site and the OpenAFS yum repository.

1. Browse to http://dl.openafs.org/dl/openafs/VERSION, where VERSION is the latest stable release of OpenAFS for Unix. Download the openafs-repository-VERSION.noarch.rpm file for Fedora systems or the openafs-repository-rhel-VERSION.noarch.rpm file for RedHat-based systems.

2. Install the downloaded RPM file using the following command:

       # rpm -U openafs-repository*.rpm

3. Install the RPM set for your operating system using the yum command as follows:

       # yum -y install openafs-client openafs-server openafs-krb5 kmod-openafs

   Alternatively, you may use dynamically-compiled kernel modules if you have the kernel headers, a compiler, and the dkms package from EPEL installed.

   To use dynamically-compiled kernel modules instead of statically compiled modules, use the following command instead of the kmod-openafs as shown above:

       # yum install openafs-client openafs-server openafs-krb5 dkms-openafs

#### Debian and Ubuntu Linux

OpenAFS is available as binary packages from the Debian linux distribution and its derivatives such as Ubuntu.

1. Install the client and server packages using the following command:

       # apt-get install openafs-client openafs-modules-dkms openafs-krb5 \
         openafs-fileserver openafs-dbserver

   You will be prompted by debconf to select your cell name and the size of your local cache.

The Debian package also includes helper scripts `afs-newcell` and `afs-rootvol`, which can automate much of the remainder of this document.

#### Systems built from source

If you are running a system where you have built the system from source yourself, you need to install the relevant components by hand:

1. Unpack the distribution tarball. The examples below assume that you have extracted and built OpenAFS in the /tmp/afsdist directory. If you pick a different location, substitute this in all of the following examples. Once you have compiled the distribution, change to the source directory as indicated.

         # cd /tmp/afsdist

2. Copy the AFS kernel library files to the local /usr/vice/etc/modload directory. The filenames for the libraries have the format libafs-version.o, where version indicates the kernel build level. The string .mp in the version indicates that the file is appropriate for machines running a multiprocessor kernel.

          # mkdir -p /usr/vice/etc/modload
          # cp -rp src/libafs/*.ko  /usr/vice/etc/modload

3. Copy the AFS initialization script to the local directory for initialization files (by convention, /etc/rc.d/init.d on Linux machines). Note the removal of the .rc extension as you copy the script.

          # cp -p src/afsd/afs.rc.linux /etc/rc.d/init.d/afs

### Configuring Server Partitions on Linux Systems

Every AFS file server machine must have at least one partition or logical volume dedicated to storing AFS volumes. Each server partition is mounted at a directory named /vicep xx, where xx is one or two lowercase letters. The /vicep xx directories must reside in the file server machine's root directory, not in one of its subdirectories (for example, /usr/vicepa is not an acceptable directory location). For additional information, see Performing Platform-Specific Procedures.

1. Create a directory called /vicep xx for each AFS server partition you are configuring (there must be at least one). Repeat the command for each partition.

          # mkdir /vicepxx

2. Add a line with the following format to the file systems registry file, /etc/fstab, for each directory just created. The entry maps the directory name to the disk partition to be mounted on it.

          /dev/disk  /vicepxx  ext2  defaults  0  2

   The following is an example for the first partition being configured.

          /dev/sda8 /vicepa ext2 defaults 0 2

3. Create a file system on each partition that is to be mounted at a /vicep xx directory. The following command is probably appropriate, but consult the Linux documentation for more information.

          # mkfs -v /dev/disk

4. Mount each partition by issuing either the mount -a command to mount all partitions at once or the mount command to mount each partition in turn.

5. If you plan to retain client functionality on this machine after completing the installation, proceed to Enabling AFS Login on Linux Systems. Otherwise, proceed to Starting the BOS Server.

### Enabling AFS Login on Linux Systems

If you plan to remove client functionality from this machine after completing the installation, skip this section and proceed to Starting the BOS Server.

At this point you incorporate AFS into the operating system's Pluggable Authentication Module (PAM) scheme. PAM integrates all authentication mechanisms on the machine, including login, to provide the security infrastructure for authenticated access to and from the machine.

You should first configure your system to obtain Kerberos v5 tickets as part of the authentication process, and then run an AFS PAM module to obtain tokens from those tickets after authentication. Many Linux distributions come with a Kerberos v5 PAM module (usually called pam-krb5 or pam_krb5), or you can download and install Russ Allbery's Kerberos v5 PAM module, which is tested regularly with AFS. See the instructions of whatever PAM module you use for how to configure it.

Some Kerberos v5 PAM modules do come with native AFS support (usually requiring the Heimdal Kerberos implementation rather than the MIT Kerberos implementation). If you are using one of those PAM modules, you can configure it to obtain AFS tokens. It's more common, however, to separate the AFS token acquisition into a separate PAM module.

The recommended AFS PAM module is Russ Allbery's pam-afs-session module. It should work with any of the Kerberos v5 PAM modules. To add it to the PAM configuration, you often only need to add configuration to the session group:

#### Linux PAM session example

    session  required  pam_afs_session.so

If you also want to obtain AFS tokens for `scp` and similar commands that don't open a session, you will also need to add the AFS PAM module to the auth group so that the PAM `setcred` call will obtain tokens. The `pam_afs_session` module will always return success for authentication so that it can be added to the auth group only for `setcred`, so make sure that it's not marked as `sufficient`.

#### Linux PAM auth example

    auth  [success=ok default=1]  pam_krb5.so
    auth  [default=done]          pam_afs_session.so
    auth  required                pam_unix.so try_first_pass

This example will work if you want to try Kerberos v5 first and then fall back to regular Unix authentication. `success=ok` for the Kerberos PAM module followed by `default=done` for the AFS PAM module will cause a successful Kerberos login to run the AFS PAM module and then skip the Unix authentication module. `default=1` on the Kerberos PAM module causes failure of that module to skip the next module (the AFS PAM module) and fall back to the Unix module. If you want to try Unix authentication first and rearrange the order, be sure to use `default=die` instead.

The PAM configuration is stored in different places in different Linux distributions. On Red Hat, look in `/etc/pam.d/system-auth`. On Debian and derivatives, look in `/etc/pam.d/common-session` and `/etc/pam.d/common-auth`.

For additional configuration examples and the configuration options of the AFS PAM module, see its documentation. For more details on the available options for the PAM configuration, see the Linux PAM documentation.

Sites which still require the deprecated `kaserver` or external Kerberos v4 authentication should consult Enabling kaserver based AFS Login on Linux Systems for details of how to enable AFS login on Linux.

Proceed to Starting the BOS Server (or if referring to these instructions while installing an additional file server machine, return to Starting Server Programs).

## Getting Started on Solaris Systems

Begin by running the AFS initialization script to call the modload program distributed by Sun Microsystems, which dynamically loads AFS modifications into the kernel. Then create partitions for storing AFS volumes, and install and configure the AFS-modified fsck program to run on AFS server partitions. If the machine is to remain an AFS client machine, incorporate AFS into the machine's Pluggable Authentication Module (PAM) scheme.

### Loading AFS into the Solaris Kernel

The modload program is the dynamic kernel loader provided by Sun Microsystems for Solaris systems. Solaris does not support incorporation of AFS modifications during a kernel build.

For AFS to function correctly, the modload program must run each time the machine reboots, so the AFS initialization script (included on the AFS CD-ROM) invokes it automatically. In this section you copy the appropriate AFS library file to the location where the modload program accesses it and then run the script.

In later sections you verify that the script correctly initializes all AFS components, then create the links that incorporate AFS into the Solaris startup and shutdown sequence.

1. Unpack the OpenAFS Solaris distribution tarball. The examples below assume that you have unpacked the files into the /tmp/afsdist directory. If you pick a diferent location, substitute this in all of the following exmaples. Once you have unpacked the distribution, change directory as indicated.

          # cd  /tmp/afsdist/sun4x_56/dest/root.client/usr/vice/etc

2. Copy the AFS initialization script to the local directory for initialization files (by convention, /etc/init.d on Solaris machines). Note the removal of the .rc extension as you copy the script.

          # cp -p  afs.rc  /etc/init.d/afs

3. Copy the appropriate AFS kernel library file to the local file /kernel/fs/afs.

   If the machine is running Solaris 11 on the x86_64 platform:

          # cp -p modload/libafs64.o /kernel/drv/amd64/afs

   If the machine is running Solaris 10 on the x86_64 platform:

          # cp -p modload/libafs64.o /kernel/fs/amd64/afs

   If the machine is running Solaris 2.6 or the 32-bit version of Solaris 7, its kernel supports NFS server functionality, and the nfsd process is running:

          # cp -p modload/libafs.o /kernel/fs/afs

   If the machine is running Solaris 2.6 or the 32-bit version of Solaris 7, and its kernel does not support NFS server functionality or the nfsd process is not running:

          # cp -p modload/libafs.nonfs.o /kernel/fs/afs

   If the machine is running the 64-bit version of Solaris 7, its kernel supports NFS server functionality, and the nfsd process is running:

          # cp -p modload/libafs64.o /kernel/fs/sparcv9/afs

   If the machine is running the 64-bit version of Solaris 7, and its kernel does not support NFS server functionality or the nfsd process is not running:

          # cp -p modload/libafs64.nonfs.o /kernel/fs/sparcv9/afs

4. Run the AFS initialization script to load AFS modifications into the kernel. You can ignore any error messages about the inability to start the BOS Server or the Cache Manager or AFS client.

          # /etc/init.d/afs start

   When an entry called `afs` does not already exist in the local /etc/name_to_sysnum file, the script automatically creates it and reboots the machine to start using the new version of the file. If this happens, log in again as the superuser root after the reboot and run the initialization script again. This time the required entry exists in the /etc/name_to_sysnum file, and the modload program runs.

          login: root
          Password: root_password
          # /etc/init.d/afs start

### Configuring the AFS-modified fsck Program on Solaris Systems

In this section, you make modifications to guarantee that the appropriate fsck program runs on AFS server partitions. The fsck program provided with the operating system must never run on AFS server partitions. Because it does not recognize the structures that the File Server uses to organize volume data, it removes all of the data. To repeat:

Never run the standard fsck program on AFS server partitions. It discards AFS volumes.

1. Create the /usr/lib/fs/afs directory to house the AFS-modified fsck program and related files.

          # mkdir /usr/lib/fs/afs
          # cd /usr/lib/fs/afs

2. Copy the vfsck binary to the newly created directory, changing the name as you do so.

          # cp  /tmp/afsdist/sun4x_56/dest/root.server/etc/vfsck  fsck

3. Working in the /usr/lib/fs/afs directory, create the following links to Solaris libraries:

          # ln -s /usr/lib/fs/ufs/clri
          # ln -s /usr/lib/fs/ufs/df
          # ln -s /usr/lib/fs/ufs/edquota
          # ln -s /usr/lib/fs/ufs/ff
          # ln -s /usr/lib/fs/ufs/fsdb
          # ln -s /usr/lib/fs/ufs/fsirand
          # ln -s /usr/lib/fs/ufs/fstyp
          # ln -s /usr/lib/fs/ufs/labelit
          # ln -s /usr/lib/fs/ufs/lockfs
          # ln -s /usr/lib/fs/ufs/mkfs
          # ln -s /usr/lib/fs/ufs/mount
          # ln -s /usr/lib/fs/ufs/ncheck
          # ln -s /usr/lib/fs/ufs/newfs
          # ln -s /usr/lib/fs/ufs/quot
          # ln -s /usr/lib/fs/ufs/quota
          # ln -s /usr/lib/fs/ufs/quotaoff
          # ln -s /usr/lib/fs/ufs/quotaon
          # ln -s /usr/lib/fs/ufs/repquota
          # ln -s /usr/lib/fs/ufs/tunefs
          # ln -s /usr/lib/fs/ufs/ufsdump
          # ln -s /usr/lib/fs/ufs/ufsrestore
          # ln -s /usr/lib/fs/ufs/volcopy

4. Append the following line to the end of the file /etc/dfs/fstypes.

          afs AFS Utilities

5. Edit the /sbin/mountall file, making two changes.

   - Add an entry for AFS to the `case` statement for option 2, so that it reads as follows:

            case "$2" in
            ufs)    foptions="-o p"
                    ;;
            afs)    foptions="-o p"
                    ;;
            s5)     foptions="-y -t /var/tmp/tmp$$ -D"
                    ;;
            *)      foptions="-y"
                    ;;

   - Edit the file so that all AFS and UFS partitions are checked in parallel. Replace the following section of code:

            # For  fsck purposes, we make a distinction between ufs and
            # other file systems
            #
            if [ "$fstype" = "ufs" ]; then
                 ufs_fscklist="$ufs_fscklist $fsckdev"
                 saveentry $fstype "$OPTIONS" $special $mountp
                 continue
            fi

     with the following section of code:

            # For fsck purposes, we make a distinction between ufs/afs
            # and other file systems.
            #
            if [ "$fstype" = "ufs" -o "$fstype" = "afs" ]; then
                 ufs_fscklist="$ufs_fscklist $fsckdev"
                 saveentry $fstype "$OPTIONS" $special $mountp
                 continue
            fi

### Configuring Server Partitions on Solaris Systems

Every AFS file server machine must have at least one partition or logical volume dedicated to storing AFS volumes. Each server partition is mounted at a directory named /vicep xx, where xx is one or two lowercase letters. The /vicep xx directories must reside in the file server machine's root directory, not in one of its subdirectories (for example, /usr/vicepa is not an acceptable directory location). For additional information, see Performing Platform-Specific Procedures.

1. Create a directory called /vicep xx for each AFS server partition you are configuring (there must be at least one). Repeat the command for each partition.

          # mkdir /vicepxx

2. Add a line with the following format to the file systems registry file, /etc/vfstab, for each partition to be mounted on a directory created in the previous step. Note the value `afs` in the fourth field, which tells Solaris to use the AFS-modified fsck program on this partition.

          /dev/dsk/disk   /dev/rdsk/disk   /vicepxx   afs   boot_order  yes

   The following is an example for the first partition being configured.

          /dev/dsk/c0t6d0s1 /dev/rdsk/c0t6d0s1 /vicepa afs 3 yes

3. Create a file system on each partition that is to be mounted at a /vicep xx directory. The following command is probably appropriate, but consult the Solaris documentation for more information.

          # newfs -v /dev/rdsk/disk

4. Issue the mountall command to mount all partitions at once.

5. If you plan to retain client functionality on this machine after completing the installation, proceed to Enabling AFS Login and Editing the File Systems Clean-up Script on Solaris Systems. Otherwise, proceed to Starting the BOS Server.

### Enabling AFS Login on Solaris Systems

If you plan to remove client functionality from this machine after completing the installation, skip this section and proceed to Starting the BOS Server.

At this point you incorporate AFS into the operating system's Pluggable Authentication Module (PAM) scheme. PAM integrates all authentication mechanisms on the machine, including login, to provide the security infrastructure for authenticated access to and from the machine.

Explaining PAM is beyond the scope of this document. It is assumed that you understand the syntax and meanings of settings in the PAM configuration file (for example, how the `other` entry works, the effect of marking an entry as `required`, `optional`, or `sufficient`, and so on).

You should first configure your system to obtain Kerberos v5 tickets as part of the authentication process, and then run an AFS PAM module to obtain tokens from those tickets after authentication. Current versions of Solaris come with a Kerberos v5 PAM module that will work, or you can download and install Russ Allbery's Kerberos v5 PAM module, which is tested regularly with AFS. See the instructions of whatever PAM module you use for how to configure it.

Some Kerberos v5 PAM modules do come with native AFS support (usually requiring the Heimdal Kerberos implementation rather than the MIT Kerberos implementation). If you are using one of those PAM modules, you can configure it to obtain AFS tokens. It's more common, however, to separate the AFS token acquisition into a separate PAM module.

The recommended AFS PAM module is Russ Allbery's pam-afs-session module. It should work with any of the Kerberos v5 PAM modules. To add it to the PAM configuration, you often only need to add configuration to the session group in `pam.conf`:

#### Solaris PAM session example

    login session required pam_afs_session.so

This example enables PAM authentication only for console login. You may want to add a similar line for the ssh service and for any other login service that you use, including possibly the `other` service (which serves as a catch-all). You may also want to add options to the AFS PAM session module (particularly `retain_after_close`, which is necessary for some versions of Solaris.

For additional configuration examples and the configuration options of the AFS PAM module, see its documentation. For more details on the available options for the PAM configuration, see the `pam.conf` manual page.

Sites which still require kaserver or external Kerberos v4 authentication should consult "Enabling kaserver based AFS Login on Solaris Systems" for details of how to enable AFS login on Solaris.

Proceed to Editing the File Systems Clean-up Script on Solaris Systems

### Editing the File Systems Clean-up Script on Solaris Systems

1. Some Solaris distributions include a script that locates and removes unneeded files from various file systems. Its conventional location is /usr/lib/fs/nfs/nfsfind. The script generally uses an argument to the find command to define which file systems to search. In this step you modify the command to exclude the /afs directory. Otherwise, the command traverses the AFS filespace of every cell that is accessible from the machine, which can take many hours. The following alterations are possibilities, but you must verify that they are appropriate for your cell.

   The first possible alteration is to add the -local flag to the existing command, so that it looks like the following:

          find $dir -local -name .nfs\* -mtime +7 -mount -exec rm -f {} \;

   Another alternative is to exclude any directories whose names begin with the lowercase letter a or a non-alphabetic character.

          find /[A-Zb-z]*  remainder of existing command

   Do not use the following command, which still searches under the /afs directory, looking for a subdirectory of type 4.2.

          find / -fstype 4.2     /* do not use */

2. Proceed to Starting the BOS Server (or if referring to these instructions while installing an additional file server machine, return to Starting Server Programs).

## Starting the BOS Server

You are now ready to start the AFS server processes on this machine. If you are not working from a packaged distribution, begin by installing the AFS server binaries to the conventional local disk location, the /usr/afs/bin directory. The following instructions also create files in other subdirectories of the /usr/afs directory.

Then obtain a krb5 keytab for use by the servers in the cell. Once the keytab is in place, issue the bosserver command to initialize the Basic OverSeer (BOS) Server, which monitors and controls other AFS server processes on its server machine. Because you have not yet configured your cell's AFS authentication and authorization mechanisms, you must always use the -localauth flag to commands, to use a printed token that does not correspond to a normal krb5 identity.

Older versions of these instructions used the -noauth flag, which completely disables all authentication and authorization checking, allowing anyone at all to control the system. Do not use this flag! It is highly insecure, and is no longer needed.

As it initializes for the first time, the BOS Server creates the following directories and files, setting the owner to the local superuser root and the mode bits to limit the ability to write (and in some cases, read) them. For a description of the contents and function of these directories and files, see the chapter in the OpenAFS Administration Guide about administering server machines. For further discussion of the mode bit settings, see Protecting Sensitive AFS Directories.

- /usr/afs/db

- /usr/afs/etc/CellServDB

- /usr/afs/etc/ThisCell

- /usr/afs/local

- /usr/afs/logs

The BOS Server also creates symbolic links called /usr/vice/etc/ThisCell and /usr/vice/etc/CellServDB to the corresponding files in the /usr/afs/etc directory. The AFS command interpreters consult the CellServDB and ThisCell files in the /usr/vice/etc directory because they generally run on client machines. On machines that are AFS servers only (as this machine currently is), the files reside only in the /usr/afs/etc directory; the links enable the command interpreters to retrieve the information they need. Later instructions for installing the client functionality replace the links with actual files.

### Generating the Cell's Kerberos V5 Keys

This guide uses krb5 for authentication; do not use the legacy kaserver for new installations.

This section creates only the cell-wide shared secret key; administrative users will be created later in the procedure. This cell-wide key has the principal name afs/cell. No user logs in under this identity, but it is used to encrypt the server tickets that the KDC grants to AFS clients for presentation to server processes during mutual authentication. (The chapter in the OpenAFS Administration Guide about cell configuration and administration describes the role of server encryption keys in mutual authentication.)

The OpenAFS 1.8.x series stores the cell-wide shared keys in the file /usr/afs/etc/KeyFileExt, whereas the 1.6.x series uses a krb5 keytab format file in /usr/afs/etc/rxkad.keytab. These instructions create both files, but populating the KeyFileExt file will only succeed using the version of asetkey from OpenAFS 1.8.x.

The examples below assume you are using MIT Kerberos. Please refer to the documentation for your KDC's administrative interface if you are using a different vendor

1. Enter kadmin interactive mode.

            # kadmin
         Authenticating as principal you/admin@YOUR REALM with password
         Password for you/admin@REALM: your_password

2. Issue the add_principal command to create a Kerberos Database entry for afs/<cell name>.

   Note that when creating the afs/<cell name> entry, the encryption type list does not include any single-DES encryption types. If such encryption types are included, additional asetkey commands will be needed to place those keys in the legacy KeyFile and ensure proper operation of the cell. For more details regarding encryption types, see the documentation for your Kerberos installation.

            kadmin: add_principal -randkey -e aes256-cts-hmac-sha1-96:normal,aes128-cts-hmac-sha1-96:normal afs/<cell name>
            Principal "afs/cell name@REALM" created.

3. Extract the newly created key for afs/cell to a keytab on the local machine.

   The keytab contains the key material that ensures the security of your AFS cell. You should ensure that it is kept in a secure location at all times.

           kadmin: ktadd -k /usr/afs/etc/rxkad.keytab -e aes256-cts-hmac-sha1-96:normal,aes128-cts-hmac-sha1-96:normal afs/<cell name>
         Entry for principal afs/<cell name> with kvno 2, encryption type aes256-cts-hmac-sha1-96 added to keytab WRFILE:/usr/afs/etc/rxkad.keytab
         Entry for principal afs/<cell name> with kvno 2, encryption type aes128-cts-hmac-sha1-96 added to keytab WRFILE:/usr/afs/etc/rxkad.keytab

   Make a note of the key version number (kvno) given in the response, as you will need it to load the key into the KeyFileExt in a later step

   Note that each time you run ktadd a new key is generated for the item being extracted. This means that you cannot run ktadd multiple times and end up with the same key material each time.

4. Issue the quit command to leave kadmin interactive mode.

            kadmin: quit

5. Issue the asetkey command to set the AFS server encryption key in the /usr/afs/etc/KeyFileExt file. This key is created from the rxkad.keytab file created earlier.

   asetkey requires the key version number (or kvno) of the afs/cell key, as well as the encryption type number of the key. You should have made note of the kvno when creating the key earlier. The key version number can also be found by running the kvno command

            # kvno -kt /usr/afs/etc/rxkad.keytab

   The encryption type numbers can be found in the local krb5 headers or the IANA registry. The most common numbers are 18 for aes256-cts-hmac-sha1-96 and 17 for aes128-cts-hmac-sha1-96.

   Once the kvno and enctypes are known, the keys can then be extracted using asetkey

            # asetkey add rxkad_krb5 <kvno>  18 /usr/afs/etc/rxkad.keytab afs/<cell name>
            # asetkey add rxkad_krb5 <kvno>  17 /usr/afs/etc/rxkad.keytab afs/<cell name>

### Starting the Server Processes

Now that the keys are in place, proceed to start the server processes:

1. If you are building from source, you need to install the compiled files to the local /usr/afs directory.

2. Issue the bosserver command.

          # /usr/afs/bin/bosserver

3. Verify that the BOS Server created /usr/vice/etc/ThisCell and /usr/vice/etc/CellServDB as symbolic links to the corresponding files in the /usr/afs/etc directory.

          # ls -l  /usr/vice/etc

   If either or both of /usr/vice/etc/ThisCell and /usr/vice/etc/CellServDB do not exist, or are not links, issue the following commands.

          # cd /usr/vice/etc
          # ln -s /usr/afs/etc/ThisCell
          # ln -s /usr/afs/etc/CellServDB

## Defining Cell Name and Membership for Server Processes

Now assign your cell's name. The chapter in the OpenAFS Administration Guide about cell configuration and administration issues discusses the important considerations, explains why changing the name is difficult, and outlines the restrictions on name format. Two of the most important restrictions are that the name cannot include uppercase letters or more than 64 characters.

Use the bos setcellname command to assign the cell name. It creates two files:

- /usr/afs/etc/ThisCell, which defines this machine's cell membership

- /usr/afs/etc/CellServDB, which lists the cell's database server machines; the machine named on the command line is placed on the list automatically

In the following and every instruction in this guide, for the machine name argument substitute the fully-qualified hostname (such as fs1.example.com) of the machine you are installing. For the cell name argument substitute your cell's complete name (such as example.com).

1. If necessary, add the directory containing the bos command to your path.

          # export PATH=$PATH:/usr/afs/bin

2. Issue the bos setcellname command to set the cell name.

          # bos setcellname <machine name> <cell name> -localauth

3. Issue the bos listhosts command to verify that the machine you are installing is now registered as the cell's first database server machine.

          # bos listhosts <machine name> -localauth
          Cell name is cell_name
              Host 1 is machine_name

## Starting the Database Server Processes

Next use the bos create command to create entries for the three database server processes in the /usr/afs/local/BosConfig file and start them running. The three processes run on database server machines only:

- The Protection Server (the ptserver process) maintains the Protection Database

- The Volume Location (VL) Server (the vlserver process) maintains the Volume Location Database (VLDB)

- The optional Backup Server (the buserver process) maintains the Backup Database

AFS ships with an additional database server named 'kaserver', which was historically used to provide authentication services to AFS cells. kaserver was based on Kerberos v4, as such, it is not recommended for new cells. This guide assumes you have already configured a Kerberos v5 realm for your site, and details the procedures required to use AFS with this realm. If you do wish to use kaserver, please see the modifications to these instructions detailed in Starting the kaserver Database Server Process

The remaining instructions in this chapter include the -cell argument on all applicable commands. Provide the cell name you assigned in Defining Cell Name and Membership for Server Processes. If a command appears on multiple lines, it is only for legibility.

1. Issue the bos create command to start the Protection Server.

          # ./bos create <machine name> ptserver simple /usr/afs/bin/ptserver -localauth

2. Issue the bos create command to start the VL Server.

          # ./bos create <machine name> vlserver simple /usr/afs/bin/vlserver -localauth

3. Optionally, issue the bos create command to start the Backup Server.

          # ./bos create <machine name> buserver simple /usr/afs/bin/buserver  -localauth

## Initializing Cell Security

If you are working with an existing cell which uses kaserver or Kerberos v4 for authentication, please see Initializing Cell Security with kaserver for installation instructions which replace this section.

Now finish initializing the cell's security mechanisms. Begin by creating the following entry in your site's Kerberos database:

- A generic administrative account, called admin by convention. If you choose to assign a different name, substitute it throughout the remainder of this document.

  After you complete the installation of the first machine, you can continue to have all administrators use the admin account, or you can create a separate administrative account for each of them. The latter scheme implies somewhat more overhead, but provides a more informative audit trail for administrative operations.

You also issue several commands that enable the new admin user to issue privileged commands in all of the AFS suites.

The following instructions do not configure all of the security mechanisms related to the AFS Backup System. See the chapter in the OpenAFS Administration Guide about configuring the Backup System.

The examples below assume you are using MIT Kerberos. Please refer to the documentation for your KDC's administrative interface if you are using a different vendor

1. Enter kadmin interactive mode.

          # kadmin
       Authenticating as principal you/admin@YOUR REALM with password
       Password for you/admin@REALM: your_password

2. Issue the add_principal command to create the Kerberos Database entry for admin.

   You should make the admin_passwd as long and complex as possible, but keep in mind that administrators need to enter it often. It must be at least six characters long.

          kadmin:  add_principal admin
          Enter password for principal "admin@REALM": admin_password
          Principal "admin@REALM" created.

3. Issue the quit command to leave kadmin interactive mode.

          kadmin: quit

4. Issue the bos adduser command to add the admin user to the /usr/afs/etc/UserList file. This enables the admin user to issue privileged bos and vos commands.

          # ./bos adduser <machine name> admin -localauth

## Initializing the Protection Database

Now continue to configure your cell's security systems by populating the Protection Database with the newly created admin user, and permitting it to issue priviledged commands on the AFS filesystem. There is nothing special about the name "admin"; it is just a convenient name for these instructions. An other name could be used throughout this document, or multiple privileged accounts created.

1. Issue the pts createuser command to create a Protection Database entry for the admin user.

   By default, the Protection Server assigns AFS UID 1 (one) to the admin user, because it is the first user entry you are creating. If the local password file (/etc/passwd or equivalent) already has an entry for admin that assigns it a UNIX UID other than 1, it is best to use the -id argument to the pts createuser command to make the new AFS UID match the existing UNIX UID. Otherwise, it is best to accept the default.

          # pts createuser -name admin [-id <AFS UID>]  -localauth
          User admin has id AFS UID

2. Issue the pts adduser command to make the admin user a member of the system:administrators group, and the pts membership command to verify the new membership. Membership in the group enables the admin user to issue privileged pts commands and some privileged fs commands.

          # ./pts adduser admin system:administrators -localauth
          # ./pts membership admin -localauth
          Groups admin (id: 1) is a member of:
            system:administrators

## Starting the File Server processes

Start the dafs process. The dafs process consists of the Demand-Attach File Server, Volume Server, Salvage Server, and Salvager (dafileserver, davolserver, salvageserver, and dasalvager processes). Most sites should run the Demand-Attach File Server, but the traditional/legacy File Server remains an option. If you are uncertain whether to run the legacy File Server, see Appendix C, The Demand-Attach File Server.

1. Issue the bos create command to start the dafs process. The commands appear here on multiple lines only for legibility.

   - Create the dafs process:

            # ./bos create  <machine name> dafs dafs /usr/afs/bin/dafileserver   \
                            /usr/afs/bin/davolserver /usr/afs/bin/salvageserver \
                            /usr/afs/bin/dasalvager -localauth

   Sometimes a message about Volume Location Database (VLDB) initialization appears, along with one or more instances of an error message similar to the following:

          FSYNC_clientInit temporary failure (will retry)

   This message appears when the volserver process tries to start before the fileserver process has completed its initialization. Wait a few minutes after the last such message before continuing, to guarantee that both processes have started successfully.

   You can verify that the dafs process has started successfully by issuing the bos status command. Its output mentions two `proc starts`.

          # ./bos status <machine name> dafs -long -localauth

2. Your next action depends on whether you have ever run AFS file server machines in the cell:

   - If you are installing the first AFS server machine ever in the cell (that is, you are not upgrading the AFS software from a previous version), create the first AFS volume, root.afs.

     For the partition name argument, substitute the name of one of the machine's AFS server partitions (such as /vicepa).

            # ./vos create  <machine name> <partition name> root.afs   \
                            -localauth

     The Volume Server produces a message confirming that it created the volume on the specified partition.

## Clock Sync Considerations

Keeping the clocks on all server and client machines in your cell synchronized is crucial to several functions, and in particular to the correct operation of AFS's distributed database technology, Ubik. The chapter in the OpenAFS Administration Guide about administering server machines explains how time skew can disturb Ubik's performance and cause service outages in your cell.

You should install and configure your time service independently of AFS. Your Kerberos realm will also require a reliable time source, so your site may already have one available.

## Overview: Installing Client Functionality

The machine you are installing is now an AFS file server machine and database server machine. Now make it a client machine by completing the following tasks:

1. Define the machine's cell membership for client processes

2. Create the client version of the CellServDB file

3. Define cache location and size

4. Create the /afs directory and start the Cache Manager

## Copying Client Files to the Local Disk

You need only undertake the steps in this section, if you are using a tar file distribution, or one built from scratch. Packaged distributions, such as RPMs or DEBs will already have installed the necessary files in the correct locations.

Before installing and configuring the AFS client, copy the necessary files from the tarball to the local /usr/vice/etc directory.

1. If you have not already done so, unpack the distribution tarball for this machine's system type into a suitable location on the filesystem, such as /tmp/afsdist. If you use a different location, substitue that in the examples that follow.

2. Copy files to the local /usr/vice/etc directory.

   This step places a copy of the AFS initialization script (and related files, if applicable) into the /usr/vice/etc directory. In the preceding instructions for incorporating AFS into the kernel, you copied the script directly to the operating system's conventional location for initialization files. When you incorporate AFS into the machine's startup sequence in a later step, you can choose to link the two files.

   On some system types that use a dynamic kernel loader program, you previously copied AFS library files into a subdirectory of the /usr/vice/etc directory. On other system types, you copied the appropriate AFS library file directly to the directory where the operating system accesses it. The following commands do not copy or recopy the AFS library files into the /usr/vice/etc directory, because on some system types the library files consume a large amount of space. If you want to copy them, add the -r flag to the first cp command and skip the second cp command.

          # cd /tmp/afsdist/sysname/root.client/usr/vice/etc
          # cp -p  *  /usr/vice/etc
          # cp -rp  C  /usr/vice/etc

## Defining Cell Membership for Client Processes

Every AFS client machine has a copy of the /usr/vice/etc/ThisCell file on its local disk to define the machine's cell membership for the AFS client programs that run on it. The ThisCell file you created in the /usr/afs/etc directory (in Defining Cell Name and Membership for Server Processes) is used only by server processes.

Among other functions, the ThisCell file on a client machine determines the following:

- The cell in which users gain tokens when they log onto the machine, assuming it is using an AFS-modified login utility

- The cell in which users gain tokens by default when they issue the aklog command

- The cell membership of the AFS server processes that the AFS command interpreters on this machine contact by default

1. Change to the /usr/vice/etc directory and remove the symbolic link created in Starting the BOS Server.

          # cd /usr/vice/etc
          # rm ThisCell

2. Create the ThisCell file as a copy of the /usr/afs/etc/ThisCell file. Defining the same local cell for both server and client processes leads to the most consistent AFS performance.

          # cp  /usr/afs/etc/ThisCell  ThisCell

## Creating the Client CellServDB File

The /usr/vice/etc/CellServDB file on a client machine's local disk lists the database server machines for each cell that the local Cache Manager can contact. If there is no entry in the file for a cell, or if the list of database server machines is wrong, then users working on this machine cannot access the cell. The chapter in the OpenAFS Administration Guide about administering client machines explains how to maintain the file after creating it.

As the afsd program initializes the Cache Manager, it copies the contents of the CellServDB file into kernel memory. The Cache Manager always consults the list in kernel memory rather than the CellServDB file itself. Between reboots of the machine, you can use the fs newcell command to update the list in kernel memory directly; see the chapter in the OpenAFS Administration Guide about administering client machines.

The AFS distribution includes the file CellServDB.dist. It includes an entry for all AFS cells that agreed to share their database server machine information at the time the distribution was created. The definitive copy of this file is maintained at grand.central.org, and updates may be obtained from /afs/grand.central.org/service/CellServDB or http://grand.central.org/dl/cellservdb/CellServDB

The CellServDB.dist file can be a good basis for the client CellServDB file, because all of the entries in it use the correct format. You can add or remove cell entries as you see fit. Depending on your cache manager configuration, additional steps (as detailed in Enabling Access to Foreign Cells) may be required to enable the Cache Manager to actually reach the cells.

In this section, you add an entry for the local cell to the local CellServDB file. The current working directory is still /usr/vice/etc.

1. Remove the symbolic link created in Starting the BOS Server and rename the CellServDB.sample file to CellServDB.

          # rm CellServDB
          # mv CellServDB.sample CellServDB

2. Add an entry for the local cell to the CellServDB file. One easy method is to use the cat command to append the contents of the server /usr/afs/etc/CellServDB file to the client version.

           # cat  /usr/afs/etc/CellServDB >>  CellServDB

   Then open the file in a text editor to verify that there are no blank lines, and that all entries have the required format, which is described just following. The ordering of cells is not significant, but it can be convenient to have the client machine's home cell at the top; move it there now if you wish.

   - The first line of a cell's entry has the following format:

            >cell_name      #organization

     where cell_name is the cell's complete Internet domain name (for example, example.com) and organization is an optional field that follows any number of spaces and the number sign (`#`). By convention it names the organization to which the cell corresponds (for example, the Example Corporation).

   - After the first line comes a separate line for each database server machine. Each line has the following format:

            IP_address   #machine_name

     where IP_address is the machine's IP address in dotted decimal format (for example, 192.12.105.3). Following any number of spaces and the number sign (`#`) is machine_name, the machine's fully-qualified hostname (for example, db1.example.com). In this case, the number sign does not indicate a comment; machine_name is a required field.

3. If the file includes cells that you do not wish users of this machine to access, remove their entries.

The following example shows entries for two cells, each of which has three database server machines:

       >example.com       #Example Corporation (home cell)
       192.12.105.3      #db1.example.com
       192.12.105.4      #db2.example.com
       192.12.105.55     #db3.example.com
       >example.org    #Example Organization cell
       138.255.68.93     #serverA.example.org
       138.255.68.72     #serverB.example.org
       138.255.33.154    #serverC.example.org

## Configuring the Cache

The Cache Manager uses a cache on the local disk or in machine memory to store local copies of files fetched from file server machines. As the afsd program initializes the Cache Manager, it sets basic cache configuration parameters according to definitions in the local /usr/vice/etc/cacheinfo file. The file has three fields:

1. The first field names the local directory on which to mount the AFS filespace. The conventional location is the /afs directory.

2. The second field defines the local disk directory to use for the disk cache. The conventional location is the /usr/vice/cache directory, but you can specify an alternate directory if another partition has more space available. There must always be a value in this field, but the Cache Manager ignores it if the machine uses a memory cache.

3. The third field specifies the number of kilobyte (1024 byte) blocks to allocate for the cache.

The values you define must meet the following requirements.

- On a machine using a disk cache, the Cache Manager expects always to be able to use the amount of space specified in the third field. Failure to meet this requirement can cause serious problems, some of which can be repaired only by rebooting. You must prevent non-AFS processes from filling up the cache partition. The simplest way is to devote a partition to the cache exclusively.

- The amount of space available in memory or on the partition housing the disk cache directory imposes an absolute limit on cache size.

- The maximum supported cache size can vary in each AFS release; see the OpenAFS Release Notes for the current version.

- For a disk cache, you cannot specify a value in the third field that exceeds 95% of the space available on the partition mounted at the directory named in the second field. If you violate this restriction, the afsd program exits without starting the Cache Manager and prints an appropriate message on the standard output stream. A value of 90% is more appropriate on most machines. Some operating systems do not automatically reserve some space to prevent the partition from filling completely; for them, a smaller value (say, 80% to 85% of the space available) is more appropriate.

- For a memory cache, you must leave enough memory for other processes and applications to run. If you try to allocate more memory than is actually available, the afsd program exits without initializing the Cache Manager and produces the following message on the standard output stream.

         afsd: memCache allocation failure at number KB

  The number value is how many kilobytes were allocated just before the failure, and so indicates the approximate amount of memory available.

Within these hard limits, the factors that determine appropriate cache size include the number of users working on the machine, the size of the files with which they work, and (for a memory cache) the number of processes that run on the machine. The higher the demand from these factors, the larger the cache needs to be to maintain good performance.

Disk caches smaller than 10 MB do not generally perform well. Machines serving multiple users usually perform better with a cache of at least 60 to 70 MB. The point at which enlarging the cache further does not really improve performance depends on the factors mentioned previously and is difficult to predict.

Memory caches smaller than 1 MB are nonfunctional, and the performance of caches smaller than 5 MB is usually unsatisfactory. Suitable upper limits are similar to those for disk caches but are probably determined more by the demands on memory from other sources on the machine (number of users and processes). Machines running only a few processes possibly can use a smaller memory cache.

### Configuring a Disk Cache

Not all file system types that an operating system supports are necessarily supported for use as the cache partition. For possible restrictions, see the OpenAFS Release Notes.

To configure the disk cache, perform the following procedures:

1. Create the local directory to use for caching. The following instruction shows the conventional location, /usr/vice/cache. If you are devoting a partition exclusively to caching, as recommended, you must also configure it, make a file system on it, and mount it at the directory created in this step.

          # mkdir /usr/vice/cache

2. Create the cacheinfo file to define the configuration parameters discussed previously. The following instruction shows the standard mount location, /afs, and the standard cache location, /usr/vice/cache.

          # echo "/afs:/usr/vice/cache:#blocks" > /usr/vice/etc/cacheinfo

   The following example defines the disk cache size as 50,000 KB:

          # echo "/afs:/usr/vice/cache:50000" > /usr/vice/etc/cacheinfo

### Configuring a Memory Cache

To configure a memory cache, create the cacheinfo file to define the configuration parameters discussed previously. The following instruction shows the standard mount location, /afs, and the standard cache location, /usr/vice/cache (though the exact value of the latter is irrelevant for a memory cache).

       # echo "/afs:/usr/vice/cache:#blocks" > /usr/vice/etc/cacheinfo

The following example allocates 25,000 KB of memory for the cache.

       # echo "/afs:/usr/vice/cache:25000" > /usr/vice/etc/cacheinfo

## Configuring the Cache Manager

By convention, the Cache Manager mounts the AFS filespace on the local /afs directory. In this section you create that directory.

The afsd program sets several cache configuration parameters as it initializes the Cache Manager, and starts daemons that improve performance. You can use the afsd command's arguments to override the parameters' default values and to change the number of some of the daemons. Depending on the machine's cache size, its amount of RAM, and how many people work on it, you can sometimes improve Cache Manager performance by overriding the default values. For a discussion of all of the afsd command's arguments, see its reference page in the OpenAFS Administration Reference.

On platforms using the standard 'afs' initialisation script (this does not apply to Fedora or RHEL based distributions), the afsd command line in the AFS initialization script on each system type includes an `OPTIONS` variable. You can use it to set nondefault values for the command's arguments, in one of the following ways:

- You can create an afsd options file that sets values for arguments to the afsd command. If the file exists, its contents are automatically substituted for the `OPTIONS` variable in the AFS initialization script. The AFS distribution for some system types includes an options file; on other system types, you must create it.

  You use two variables in the AFS initialization script to specify the path to the options file: `CONFIG` and `AFSDOPT`. On system types that define a conventional directory for configuration files, the `CONFIG` variable indicates it by default; otherwise, the variable indicates an appropriate location.

  List the desired afsd options on a single line in the options file, separating each option with one or more spaces. The following example sets the -stat argument to 2500, the -daemons argument to 4, and the -volumes argument to 100.

         -stat 2500 -daemons 4 -volumes 100

- On a machine that uses a disk cache, you can set the `OPTIONS` variable in the AFS initialization script to one of `$SMALL`, `$MEDIUM`, or `$LARGE`. The AFS initialization script uses one of these settings if the afsd options file named by the `AFSDOPT` variable does not exist. In the script as distributed, the `OPTIONS` variable is set to the value `$MEDIUM`.

  Do not set the `OPTIONS` variable to `$SMALL`, `$MEDIUM`, or `$LARGE` on a machine that uses a memory cache. The arguments it sets are appropriate only on a machine that uses a disk cache.

  The script (or on some system types the afsd options file named by the `AFSDOPT` variable) defines a value for each of `SMALL`, `MEDIUM`, and `LARGE` that sets afsd command arguments appropriately for client machines of different sizes:

  - `SMALL` is suitable for a small machine that serves one or two users and has approximately 8 MB of RAM and a 20-MB cache

  - `MEDIUM` is suitable for a medium-sized machine that serves two to six users and has 16 MB of RAM and a 40-MB cache

  - `LARGE` is suitable for a large machine that serves five to ten users and has 32 MB of RAM and a 100-MB cache

- You can choose not to create an afsd options file and to set the `OPTIONS` variable in the initialization script to a null value rather than to the default `$MEDIUM` value. You can then either set arguments directly on the afsd command line in the script, or set no arguments (and so accept default values for all Cache Manager parameters).

If you are running on a Fedora or RHEL based system, the openafs-client initialization script behaves differently from that described above. It sources /etc/sysconfig/openafs, in which the AFSD_ARGS variable may be set to contain any, or all, of the afsd options detailed. Note that this script does not support setting an OPTIONS variable, or the SMALL, MEDIUM and LARGE methods of defining cache size

1. Create the local directory on which to mount the AFS filespace, by convention /afs. If the directory already exists, verify that it is empty.

          # mkdir /afs

2. On non-package based Linux systems, copy the afsd options file from the /usr/vice/etc directory to the /etc/sysconfig directory, removing the .conf extension as you do so.

          # cp /usr/vice/etc/afs.conf /etc/sysconfig/afs

3. Edit the machine's AFS initialization script or afsd options file to set appropriate values for afsd command parameters. The script resides in the indicated location on each system type:

   - On Fedora and RHEL systems, /etc/sysconfg/openafs

   - On non-package based Linux systems, /etc/sysconfig/afs (the afsd options file)

   - On Solaris systems, /etc/init.d/afs

   Use one of the methods described in the introduction to this section to add the following flags to the afsd command line. If you intend for the machine to remain an AFS client, also set any performance-related arguments you wish.

   - Add the -memcache flag if the machine is to use a memory cache.

   - Add the -verbose flag to display a trace of the Cache Manager's initialization on the standard output stream.

In order to successfully complete the instructions in the remainder of this guide, it is important that the machine does not have a synthetic root (as discussed in Enabling Access to Foreign Cells). As some distributions ship with this enabled, it may be necessary to remove any occurences of the -dynroot and -afsdb options from both the AFS initialisation script and options file. If this functionality is required it may be renabled as detailed in Enabling Access to Foreign Cells.

## Overview: Completing the Installation of the First AFS Machine

The machine is now configured as an AFS file server and client machine. In this final phase of the installation, you initialize the Cache Manager and then create the upper levels of your AFS filespace, among other procedures. The procedures are:

1. Verify that the initialization script works correctly, and incorporate it into the operating system's startup and shutdown sequence

2. Create and mount top-level volumes

3. Create and mount volumes to store system binaries in AFS

4. Enable access to foreign cells

5. Institute additional security measures

6. Remove client functionality if desired

## Verifying the AFS Initialization Script

At this point you run the AFS initialization script to verify that it correctly invokes all of the necessary programs and AFS processes, and that they start correctly. The following are the relevant commands:

- The command that dynamically loads AFS modifications into the kernel, on some system types (not applicable if the kernel has AFS modifications built in)

- The bosserver command, which starts the BOS Server; it in turn starts the server processes for which you created entries in the /usr/afs/local/BosConfig file

- The afsd command, which initializes the Cache Manager

On system types that use a dynamic loader program, you must reboot the machine before running the initialization script, so that it can freshly load AFS modifications into the kernel.

If there are problems during the initialization, attempt to resolve them. The OpenAFS mailing lists can provide assistance if necessary.

1. Issue the bos shutdown command to shut down the AFS server processes other than the BOS Server. Include the -wait flag to delay return of the command shell prompt until all processes shut down completely.

          # /usr/afs/bin/bos shutdown <machine name> -wait

2. Issue the ps command to learn the bosserver process's process ID number (PID), and then the kill command to stop it.

          # ps appropriate_ps_options | grep bosserver
          # kill bosserver_PID

3. Issue the appropriate commands to run the AFS initialization script for this system type.

   On Linux systems:

   1. Reboot the machine and log in again as the local superuser root.

             # cd /
             # shutdown -r now
             login: root
             Password: root_password

   2. Run the AFS initialization scripts.

             # /etc/rc.d/init.d/openafs-client  start
             # /etc/rc.d/init.d/openafs-server  start

   On Solaris systems:

   1. Reboot the machine and log in again as the local superuser root.

             # cd /
             # shutdown -i6 -g0 -y
             login: root
             Password: root_password

   2. Run the AFS initialization script.

             # /etc/init.d/afs  start

4. Wait for the message that confirms that Cache Manager initialization is complete.

   On machines that use a disk cache, it can take a while to initialize the Cache Manager for the first time, because the afsd program must create all of the V n files in the cache directory. Subsequent Cache Manager initializations do not take nearly as long, because the V n files already exist.

5. If you are working with an existing cell which uses kaserver for authentication, please recall the note in Using this Appendix detailing the substitution of kinit and aklog with klog.

   As a basic test of correct AFS functioning, issue the kinit and aklog commands to authenticate as the admin user. Provide the password (admin_passwd) you defined in Initializing Cell Security.

          # kinit admin
          Password:  admin_passwd
          # aklog

6. Issue the tokens command to verify that the aklog command worked correctly. If it did, the output looks similar to the following example for the example.com cell, where admin's AFS UID is 1. If the output does not seem correct, resolve the problem. Changes to the AFS initialization script are possibly necessary. The OpenAFS mailing lists can provide assistance as necessary.

          # tokens
          Tokens held by the Cache Manager:
          User's (AFS ID 1) tokens for afs@example.com [Expires May 22 11:52]
              --End of list--

7. Issue the bos status command to verify that the output for each process reads `Currently running normally`.

          # /usr/afs/bin/bos status <machine name>

8. Change directory to the local file system root (/) and issue the fs checkvolumes command.

          # cd /
          # /usr/afs/bin/fs checkvolumes

## Activating the AFS Initialization Script

Now that you have confirmed that the AFS initialization script works correctly, take the action necessary to have it run automatically at each reboot. Proceed to the instructions for your system type:

- Activating the Script on Linux Systems

- Activating the Script on Solaris Systems

### Activating the Script on Linux Systems

1. Issue the chkconfig command to activate the openafs-client and openafs-server configuration variables. Based on the instruction in the AFS initialization file that begins with the string `#chkconfig`, the command automatically creates the symbolic links that incorporate the script into the Linux startup and shutdown sequence.

          # /sbin/chkconfig  --add openafs-client
          # /sbin/chkconfig  --add openafs-server

2. (Optional) There are now copies of the AFS initialization file in both the /usr/vice/etc and /etc/rc.d/init.d directories, and copies of the afsd options file in both the /usr/vice/etc and /etc/sysconfig directories. If you want to avoid potential confusion by guaranteeing that the two copies of each file are always the same, create a link between them. You can always retrieve the original script or options file from the AFS CD-ROM if necessary.

          # cd /usr/vice/etc
          # rm afs.rc afs.conf
          # ln -s  /etc/rc.d/init.d/afs  afs.rc
          # ln -s  /etc/sysconfig/afs  afs.conf

3. Proceed to Configuring the Top Levels of the AFS Filespace.

### Activating the Script on Solaris Systems

1. Change to the /etc/init.d directory and issue the ln -s command to create symbolic links that incorporate the AFS initialization script into the Solaris startup and shutdown sequence.

          # cd /etc/init.d
          # ln -s ../init.d/afs /etc/rc3.d/S99afs
          # ln -s ../init.d/afs /etc/rc0.d/K66afs

2. (Optional) There are now copies of the AFS initialization file in both the /usr/vice/etc and /etc/init.d directories. If you want to avoid potential confusion by guaranteeing that they are always the same, create a link between them. You can always retrieve the original script from the AFS CD-ROM if necessary.

          # cd /usr/vice/etc
          # rm afs.rc
          # ln -s  /etc/init.d/afs  afs.rc

## Configuring the Top Levels of the AFS Filespace

If you have not previously run AFS in your cell, you now configure the top levels of your cell's AFS filespace. If you have run a previous version of AFS, the filespace is already configured. Proceed to Storing AFS Binaries in AFS.

You created the root.afs volume in Starting the File Server, Volume Server, and Salvager, and the Cache Manager mounted it automatically on the local /afs directory when you ran the AFS initialization script in Verifying the AFS Initialization Script. You now set the access control list (ACL) on the /afs directory; creating, mounting, and setting the ACL are the three steps required when creating any volume.

After setting the ACL on the root.afs volume, you create your cell's root.cell volume, mount it as a subdirectory of the /afs directory, and set the ACL. Create both a read/write and a regular mount point for the root.cell volume. The read/write mount point enables you to access the read/write version of replicated volumes when necessary. Creating both mount points essentially creates separate read-only and read-write copies of your filespace, and enables the Cache Manager to traverse the filespace on a read-only path or read/write path as appropriate. For further discussion of these concepts, see the chapter in the OpenAFS Administration Guide about administering volumes.

Then replicate both the root.afs and root.cell volumes. This is required if you want to replicate any other volumes in your cell, because all volumes mounted above a replicated volume must themselves be replicated in order for the Cache Manager to access the replica.

When the root.afs volume is replicated, the Cache Manager is programmed to access its read-only version (root.afs.readonly) whenever possible. To make changes to the contents of the root.afs volume (when, for example, you mount another cell's root.cell volume at the second level in your filespace), you must mount the root.afs volume temporarily, make the changes, release the volume and remove the temporary mount point. For instructions, see Enabling Access to Foreign Cells.

1. Issue the fs setacl command to edit the ACL on the /afs directory. Add an entry that grants the l (lookup) and r (read) permissions to the system:anyuser group, to enable all AFS users who can reach your cell to traverse through the directory. If you prefer to enable access only to locally authenticated users, substitute the system:authuser group.

   Note that there is already an ACL entry that grants all seven access rights to the system:administrators group. It is a default entry that AFS places on every new volume's root directory.

   The top-level AFS directory, typically /afs, is a special case: when the client is configured to run in dynroot mode (e.g. afsd -dynroot, attempts to set the ACL on this directory will return Connection timed out. This is because the dynamically- generated root directory is not a part of the global AFS space, and cannot have an access control list set on it.

          # /usr/afs/bin/fs setacl /afs system:anyuser rl

2. Issue the vos create command to create the root.cell volume. Then issue the fs mkmount command to mount it as a subdirectory of the /afs directory, where it serves as the root of your cell's local AFS filespace. Finally, issue the fs setacl command to create an ACL entry for the system:anyuser group (or system:authuser group).

   For the partition name argument, substitute the name of one of the machine's AFS server partitions (such as /vicepa). For the cellname argument, substitute your cell's fully-qualified Internet domain name (such as example.com).

          # /usr/afs/bin/vos create  <machine name> <partition name> root.cell
          # /usr/afs/bin/fs mkmount /afs/cellname  root.cell
          # /usr/afs/bin/fs setacl /afs/cellname  system:anyuser rl

3. (Optional) Create a symbolic link to a shortened cell name, to reduce the length of pathnames for users in the local cell. For example, in the example.com cell, /afs/example is a link to /afs/example.com.

          # cd /afs
          # ln -s  full_cellname  short_cellname

4. Issue the fs mkmount command to create a read/write mount point for the root.cell volume (you created a regular mount point in Step 2).

   By convention, the name of a read/write mount point begins with a period, both to distinguish it from the regular mount point and to make it visible only when the -a flag is used on the ls command.

   Change directory to /usr/afs/bin to make it easier to access the command binaries.

          # cd /usr/afs/bin
          # ./fs mkmount   /afs/.cellname   root.cell -rw

5. Issue the vos addsite command to define a replication site for both the root.afs and root.cell volumes. In each case, substitute for the partition name argument the partition where the volume's read/write version resides. When you install additional file server machines, it is a good idea to create replication sites on them as well.

          # ./vos addsite <machine name> <partition name> root.afs
          # ./vos addsite <machine name> <partition name> root.cell

6. Issue the fs examine command to verify that the Cache Manager can access both the root.afs and root.cell volumes, before you attempt to replicate them. The output lists each volume's name, volumeID number, quota, size, and the size of the partition that houses them. If you get an error message instead, do not continue before taking corrective action.

          # ./fs examine /afs
          # ./fs examine /afs/cellname

7. Issue the vos release command to release a replica of the root.afs and root.cell volumes to the sites you defined in Step 5.

          # ./vos release root.afs
          # ./vos release root.cell

8. Issue the fs checkvolumes to force the Cache Manager to notice that you have released read-only versions of the volumes, then issue the fs examine command again. This time its output mentions the read-only version of the volumes (root.afs.readonly and root.cell.readonly) instead of the read/write versions, because of the Cache Manager's bias to access the read-only version of the root.afs volume if it exists.

          # ./fs checkvolumes
          # ./fs examine /afs
          # ./fs examine /afs/cellname

## Storing AFS Binaries in AFS

Sites with existing binary distribution mechanisms, including those which use packaging systems such as RPM, may wish to skip this step, and use tools native to their operating system to manage AFS configuration information.

In the conventional configuration, you make AFS client binaries and configuration files available in the subdirectories of the /usr/afsws directory on client machines (afsws is an acronym for AFS w ork s tation). You can conserve local disk space by creating /usr/afsws as a link to an AFS volume that houses the AFS client binaries and configuration files for this system type.

In this section you create the necessary volumes. The conventional location to which to link /usr/afsws is /afs/cellname/sysname/usr/afsws, where sysname is the appropriate system type name as specified in the OpenAFS Release Notes. The instructions in Installing Additional Client Machines assume that you have followed the instructions in this section.

If you have previously run AFS in the cell, the volumes possibly already exist. If so, you need to perform Step 8 only.

The current working directory is still /usr/afs/bin, which houses the fs and vos command suite binaries. In the following commands, it is possible you still need to specify the pathname to the commands, depending on how your PATH environment variable is set.

1. Issue the vos create command to create volumes for storing the AFS client binaries for this system type. The following example instruction creates volumes called sysname, sysname.usr, and sysname.usr.afsws. Refer to the OpenAFS Release Notes to learn the proper value of sysname for this system type.

          # vos create <machine name> <partition name> sysname
          # vos create <machine name> <partition name> sysname.usr
          # vos create <machine name> <partition name> sysname.usr.afsws

2. Issue the fs mkmount command to mount the newly created volumes. Because the root.cell volume is replicated, you must precede the cellname part of the pathname with a period to specify the read/write mount point, as shown. Then issue the vos release command to release a new replica of the root.cell volume, and the fs checkvolumes command to force the local Cache Manager to access them.

          # fs mkmount -dir /afs/.cellname/sysname -vol sysname
          # fs mkmount -dir /afs/.cellname/sysname/usr  -vol sysname.usr
          # fs mkmount -dir /afs/.cellname/sysname/usr/afsws -vol sysname.usr.afsws
          # vos release root.cell
          # fs checkvolumes

3. Issue the fs setacl command to grant the l (lookup) and r (read) permissions to the system:anyuser group on each new directory's ACL.

          # cd /afs/.cellname/sysname
          # fs setacl  -dir  .  usr  usr/afsws  -acl  system:anyuser rl

4. Issue the fs setquota command to set an unlimited quota on the volume mounted at the /afs/cellname/sysname/usr/afsws directory. This enables you to copy all of the appropriate files from the CD-ROM into the volume without exceeding the volume's quota.

   If you wish, you can set the volume's quota to a finite value after you complete the copying operation. At that point, use the vos examine command to determine how much space the volume is occupying. Then issue the fs setquota command to set a quota that is slightly larger.

          # fs setquota /afs/.cellname/sysname/usr/afsws  0

5. Unpack the distribution tarball into the /tmp/afsdist directory, if it is not already.

6. Copy the contents of the indicated directories from the distribution into the /afs/cellname/sysname/usr/afsws directory.

          # cd /afs/.cellname/sysname/usr/afsws
          # cp -rp /tmp/afsdist/sysname/bin  .
          # cp -rp /tmp/afsdist/sysname/etc  .
          # cp -rp /tmp/afsdist/sysname/include  .
          # cp -rp /tmp/afsdist/sysname/lib  .

7. Create /usr/afsws on the local disk as a symbolic link to the directory /afs/cellname/@sys/usr/afsws. You can specify the actual system name instead of @sys if you wish, but the advantage of using @sys is that it remains valid if you upgrade this machine to a different system type.

          # ln -s /afs/cellname/@sys/usr/afsws  /usr/afsws

8. (Optional) To enable users to issue commands from the AFS suites (such as fs) without having to specify a pathname to their binaries, include the /usr/afsws/bin and /usr/afsws/etc directories in the PATH environment variable you define in each user's shell initialization file (such as .cshrc).

## Storing AFS Documents in AFS

The AFS distribution includes the following documents:

- OpenAFS Release Notes

- OpenAFS Quick Beginnings

- OpenAFS User Guide

- OpenAFS Administration Reference

- OpenAFS Administration Guide

OpenAFS Documentation is not currently provided with all distributions, but may be downloaded separately from the OpenAFS website

The OpenAFS Documentation Distribution has a directory for each document format provided. The different formats are suitable for online viewing, printing, or both.

This section explains how to create and mount a volume to house the documents, making them available to your users. The recommended mount point for the volume is /afs/cellname/afsdoc. If you wish, you can create a link to the mount point on each client machine's local disk, called /usr/afsdoc. Alternatively, you can create a link to the mount point in each user's home directory. You can also choose to permit users to access only certain documents (most probably, the OpenAFS User Guide) by creating different mount points or setting different ACLs on different document directories.

The current working directory is still /usr/afs/bin, which houses the fs and vos command suite binaries you use to create and mount volumes. In the following commands, it is possible you still need to specify the pathname to the commands, depending on how your PATH environment variable is set.

1. Issue the vos create command to create a volume for storing the AFS documentation. Include the -maxquota argument to set an unlimited quota on the volume. This enables you to copy all of the appropriate files from the CD-ROM into the volume without exceeding the volume's quota.

   If you wish, you can set the volume's quota to a finite value after you complete the copying operations. At that point, use the vos examine command to determine how much space the volume is occupying. Then issue the fs setquota command to set a quota that is slightly larger.

          # vos create  <machine name> <partition name>  afsdoc  -maxquota  0

2. Issue the fs mkmount command to mount the new volume. Because the root.cell volume is replicated, you must precede the cellname with a period to specify the read/write mount point, as shown. Then issue the vos release command to release a new replica of the root.cell volume, and the fs checkvolumes command to force the local Cache Manager to access them.

          # fs mkmount -dir /afs/.cellname/afsdoc -vol afsdoc
          # vos release root.cell
          # fs checkvolumes

3. Issue the fs setacl command to grant the rl permissions to the system:anyuser group on the new directory's ACL.

          # cd /afs/.cellname/afsdoc
          # fs setacl  .  system:anyuser rl

4. Unpack the OpenAFS documentation distribution into the /tmp/afsdocs directory. You may use a different directory, in which case the location you use should be subsituted in the following examples. For instructions on unpacking the distribution, consult the documentation for your operating system's tar command.

5. Copy the AFS documents in one or more formats from the unpacked distribution into subdirectories of the /afs/cellname/afsdoc directory. Repeat the commands for each format.

          # mkdir format_name
          # cd format_name
          # cp -rp /tmp/afsdocs/format  .

   If you choose to store the HTML version of the documents in AFS, note that in addition to a subdirectory for each document there are several files with a .gif extension, which enable readers to move easily between sections of a document. The file called index.htm is an introductory HTML page that contains a hyperlink to each of the documents. For online viewing to work properly, these files must remain in the top-level HTML directory (the one named, for example, /afs/cellname/afsdoc/html).

6. (Optional) If you believe it is helpful to your users to access the AFS documents in a certain format via a local disk directory, create /usr/afsdoc on the local disk as a symbolic link to the documentation directory in AFS (/afs/cellname/afsdoc/format_name).

          # ln -s /afs/cellname/afsdoc/format_name /usr/afsdoc

   An alternative is to create a link in each user's home directory to the /afs/cellname/afsdoc/format_name directory.

## Storing System Binaries in AFS

You can also choose to store other system binaries in AFS volumes, such as the standard UNIX programs conventionally located in local disk directories such as /etc, /bin, and /lib. Storing such binaries in an AFS volume not only frees local disk space, but makes it easier to update binaries on all client machines.

The following is a suggested scheme for storing system binaries in AFS. It does not include instructions, but you can use the instructions in Storing AFS Binaries in AFS (which are for AFS-specific binaries) as a template.

Some files must remain on the local disk for use when AFS is inaccessible (during bootup and file server or network outages). The required binaries include the following:

- A text editor, network commands, and so on

- Files used during the boot sequence before the afsd program runs, such as initialization and configuration files, and binaries for commands that mount file systems

- Files used by dynamic kernel loader programs

In most cases, it is more secure to enable only locally authenticated users to access system binaries, by granting the l (lookup) and r (read) permissions to the system:authuser group on the ACLs of directories that contain the binaries. If users need to access a binary while unauthenticated, however, the ACL on its directory must grant those permissions to the system:anyuser group.

The following chart summarizes the suggested volume and mount point names for storing system binaries. It uses a separate volume for each directory. You already created a volume called sysname for this machine's system type when you followed the instructions in Storing AFS Binaries in AFS.

You can name volumes in any way you wish, and mount them at other locations than those suggested here. However, this scheme has several advantages:

- Volume names clearly identify volume contents

- Using the sysname prefix on every volume makes it is easy to back up all of the volumes together, because the AFS Backup System enables you to define sets of volumes based on a string included in all of their names

- It makes it easy to track related volumes, keeping them together on the same file server machine if desired

- There is a clear relationship between volume name and mount point name

Volume Name | Mount Point
--- | ---
sysname | /afs/cellname/sysname
sysname.bin | /afs/cellname/sysname/bin
sysname.etc | /afs/cellname/sysname/etc
sysname.usr | /afs/cellname/sysname/usr
sysname.usr.afsws | /afs/cellname/sysname/usr/afsws
sysname.usr.bin | /afs/cellname/sysname/usr/bin
sysname.usr.etc | /afs/cellname/sysname/usr/etc
sysname.usr.inc | /afs/cellname/sysname/usr/include
sysname.usr.lib | /afs/cellname/sysname/usr/lib
sysname.usr.loc | /afs/cellname/sysname/usr/local
sysname.usr.man | /afs/cellname/sysname/usr/man
sysname.usr.sys | /afs/cellname/sysname/usr/sys

## Enabling Access to Foreign Cells

With current OpenAFS releases, there exist a number of mechanisms for providing access to foreign cells. You may add mount points in your AFS filespace for each foreign cell you wish users to access, or you can enable a 'synthetic' AFS root, which contains mountpoints for either all AFS cells defined in the client machine's local /usr/vice/etc/CellServDB, or for all cells providing location information in the DNS.

### Enabling a Synthetic AFS root

When a synthetic root is enabled, the client cache machine creates its own root.afs volume, rather than using the one provided with your cell. This allows clients to access all cells in the CellServDB file and, optionally, all cells registered in the DNS, without requiring system administrator action to enable this access. Using a synthetic root has the additional advantage that it allows a client to start its AFS service without a network available, as it is no longer necessary to contact a fileserver to obtain the root volume.

OpenAFS supports two complimentary mechanisms for creating the synthetic root. Starting the cache manager with the -dynroot option adds all cells listed in /usr/vice/etc/CellServDB to the client's AFS root. Adding the -afsdb option in addition to this enables DNS lookups for any cells that are not found in the client's CellServDB file. Both of these options are added to the AFS initialisation script, or options file, as detailed in Configuring the Cache Manager.

### Adding foreign cells to a conventional root volume

In this section you create a mount point in your AFS filespace for the root.cell volume of each foreign cell that you want to enable your users to access. For users working on a client machine to access the cell, there must in addition be an entry for it in the client machine's local /usr/vice/etc/CellServDB file. (The instructions in Creating the Client CellServDB File suggest that you use the CellServDB.sample file included in the AFS distribution as the basis for your cell's client CellServDB file. The sample file lists all of the cells that had agreed to participate in the AFS global namespace at the time your AFS CD-ROM was created. As mentioned in that section, the AFS Product Support group also maintains a copy of the file, updating it as necessary.)

The chapter in the OpenAFS Administration Guide about cell administration and configuration issues discusses the implications of participating in the global AFS namespace. The chapter about administering client machines explains how to maintain knowledge of foreign cells on client machines, and includes suggestions for maintaining a central version of the file in AFS.

1. Issue the fs mkmount command to mount each foreign cell's root.cell volume on a directory called /afs/foreign_cell. Because the root.afs volume is replicated, you must create a temporary mount point for its read/write version in a directory to which you have write access (such as your cell's /afs/.cellname directory). Create the mount points, issue the vos release command to release new replicas to the read-only sites for the root.afs volume, and issue the fs checkvolumes command to force the local Cache Manager to access the new replica.

   You need to issue the fs mkmount command only once for each foreign cell's root.cell volume. You do not need to repeat the command on each client machine.

   Substitute your cell's name for cellname.

          # cd /afs/.cellname
          # /usr/afs/bin/fs  mkmount  temp  root.afs

   Repeat the fs mkmount command for each foreign cell you wish to mount at this time.

          # /usr/afs/bin/fs mkmount temp/foreign_cell root.cell -c foreign_cell

   Issue the following commands only once.

          # /usr/afs/bin/fs rmmount temp
          # /usr/afs/bin/vos release root.afs
          # /usr/afs/bin/fs checkvolumes

2. If this machine is going to remain an AFS client after you complete the installation, verify that the local /usr/vice/etc/CellServDB file includes an entry for each foreign cell.

   For each cell that does not already have an entry, complete the following instructions:

   1. Create an entry in the CellServDB file. Be sure to comply with the formatting instructions in Creating the Client CellServDB File.

   2. Issue the fs newcell command to add an entry for the cell directly to the list that the Cache Manager maintains in kernel memory. Provide each database server machine's fully qualified hostname.

             # /usr/afs/bin/fs newcell <foreign_cell> <dbserver1>    \
                      [<dbserver2>] [<dbserver3>]

   3. If you plan to maintain a central version of the CellServDB file (the conventional location is /afs/cellname/common/etc/CellServDB), create it now as a copy of the local /usr/vice/etc/CellServDB file. Verify that it includes an entry for each foreign cell you want your users to be able to access.

             # mkdir common
             # mkdir common/etc
             # cp  /usr/vice/etc/CellServDB  common/etc
             # /usr/afs/bin/vos release root.cell

3. Issue the ls command to verify that the new cell's mount point is visible in your filespace. The output lists the directories at the top level of the new cell's AFS filespace.

          # ls /afs/foreign_cell

4. If you wish to participate in the global AFS namespace, and only intend running one database server, please register your cell with grand.central.org at this time. To do so, email the CellServDB fragment describing your cell, together with a contact name and email address for any queries, to cellservdb@grand.central.org. If you intend on deploying multiple database servers, please wait until you have installed all of them before registering your cell.

5. If you wish to allow your cell to be located through DNS lookups, at this time you should also add the necessary configuration to your DNS.

   AFS database servers may be located by creating AFSDB records in the DNS for the domain name corresponding to the name of your cell. It's outside the scope of this guide to give an indepth description of managing, or configuring, your site's DNS. You should consult the documentation for your DNS server for further details on AFSDB records.

## Improving Cell Security

This section discusses ways to improve the security of AFS data in your cell. Also see the chapter in the OpenAFS Administration Guide about configuration and administration issues.

### Controlling root Access

As on any machine, it is important to prevent unauthorized users from logging onto an AFS server or client machine as the local superuser root. Take care to keep the root password secret.

The local root superuser does not have special access to AFS data through the Cache Manager (as members of the system:administrators group do), but it does have the following privileges:

- On client machines, the ability to issue commands from the fs suite that affect AFS performance

- On server machines, the ability to disable authorization checking, or to install rogue process binaries

### Controlling System Administrator Access

Following are suggestions for managing AFS administrative privilege:

- Create an administrative account for each administrator named something like username.admin. Administrators authenticate under these identities only when performing administrative tasks, and destroy the administrative tokens immediately after finishing the task (either by issuing the unlog command, or the kinit and aklog commands to adopt their regular identity).

- Set a short ticket lifetime for administrator accounts (for example, 20 minutes) by using the facilities of your KDC. For instance, with a MIT Kerberos KDC, this can be performed using the --max-ticket-life argument to the kadmin modify_principal command. Do not however, use a short lifetime for users who issue long-running backup commands.

- Limit the number of system administrators in your cell, especially those who belong to the system:administrators group. By default they have all ACL rights on all directories in the local AFS filespace, and therefore must be trusted not to examine private files.

- Limit the use of system administrator accounts on machines in public areas. It is especially important not to leave such machines unattended without first destroying the administrative tokens.

- Limit the use by administrators of standard UNIX commands that make connections to remote machines (such as the telnet utility). Many of these programs send passwords across the network without encrypting them.

### Protecting Sensitive AFS Directories

Some subdirectories of the /usr/afs directory contain files crucial to cell security. Unauthorized users must not read or write to these files because of the potential for misuse of the information they contain.

As the BOS Server initializes for the first time on a server machine, it creates several files and directories (as mentioned in Starting the BOS Server). It sets their owner to the local superuser root and sets their mode bits to enable writing by the owner only; in some cases, it also restricts reading.

At each subsequent restart, the BOS Server checks that the owner and mode bits on these files are still set appropriately. If they are not, it write the following message to the /usr/afs/logs/BosLog file:

       Bosserver reports inappropriate access on server directories

The BOS Server does not reset the mode bits, which enables you to set alternate values if you wish.

The following charts lists the expected mode bit settings. A question mark indicates that the BOS Server does not check that mode bit.

/usr/afs | `drwxr`?`xr-x`
/usr/afs/backup | `drwx`???`---`
/usr/afs/bin | `drwxr`?`xr-x`
/usr/afs/db | `drwx`???`---`
/usr/afs/etc | `drwxr`?`xr-x`
/usr/afs/etc/KeyFile | `-rw`????`---`
/usr/afs/etc/UserList | `-rw`?????`--`
/usr/afs/local | `drwx`???`---`
/usr/afs/logs | `drwxr`?`xr-x`

## Removing Client Functionality

Follow the instructions in this section only if you do not wish this machine to remain an AFS client. Removing client functionality means that you cannot use this machine to access AFS files.

1. Remove the files from the /usr/vice/etc directory. The command does not remove the directory for files used by the dynamic kernel loader program, if it exists on this system type. Those files are still needed on a server-only machine.

          # cd /usr/vice/etc
          # rm  *
          # rm -rf  C

2. Create symbolic links to the ThisCell and CellServDB files in the /usr/afs/etc directory. This makes it possible to issue commands from the AFS command suites (such as bos and fs) on this machine.

          # ln -s /usr/afs/etc/ThisCell ThisCell
          # ln -s /usr/afs/etc/CellServDB CellServDB

3. Reboot the machine. Most system types use the shutdown command, but the appropriate options vary.

          # cd /
          # shutdown appropriate_options