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Setting up an AFS server under Debian

A lot of this should translate to other distributions as well, but YMMV.

Before you start

This section is almost definately OS/Distro independant.

Kerberos

AFS depends on a working Kerberos installation. Refer to KerberosNotes.

Filesystems and Partitions

Though AFS seems fairly filesystem independant, it really prefers having a seperate partition for your AFS cell. Apparently it requires a different fsck(8) for magical reasons too, so its probably best to follow this. Put your first partition on /vicepa, and your second on /vicepb, and so on. You can also use the namei backend which is slow, but is FS/OS independant, provided you can do normal filesystem stuff.

Hostname

Some people report AFS required their server's hostname to resolve properly via DNS, or they'd get weird problems for no apparent reason. This does not seem to be consistent and might be Kerberos issue.

Kernel

Make sure AFS likes your kernel before continuing, or else things may fail for no good reason. Some people report problems with AFS on kernel versions others have no trouble with, so check your own setup.

Installing AFS

Installing the packages:

The pertinent Debian packages are

  • openafs-dbserver
  • openafs-krb5
  • openafs-client

Your cellname should be your lower-case DNS name, eg element.tla. Your DBServer for AFS should be the DNS name of the machine you are installing on currently.

Setting up Kerberos

Run the following commands (but see below first)

kadmin.local -e des-cbc-crc:v4

addprinc -randkey afs ktadd -k /tmp/afs.keytab afs quit

kadmin.local

addprinc root

(enter passwords)

quit

asetkey add 3 /tmp/afs.keytab afs

Adding a princ for root is probaby a bad idea. The "Kerberos Way" is to have user/instance, eg joeshmoe/admin, known to AFS as joeshmoe.admin.

Partitions

Make sure you have a partition created and mounted at /vicepa. If you cant do this with a real partition, make a loopback one as follows
dd if=/dev/zero of=/var/lib/openafs/vicepa bs=1024k count=32 mke2fs /var/lib/openafs/vicepa mkdir /vicepa && mount -oloop /var/lib/openafs/vicepa /vicepa

You can later add /vicepb, /vicepc etc.

Set up the cell

Make sure /etc/openafs/!ThisCell? looks something like

element.tla

and /etc/openafs/!CellServDb? resembles

element.tla # cell

10.66.1.101 # afs.element.tla

At this point, make sure you have compiled the OpenAFS modules for your kernel. If you build a new kernel at the same time, reboot now so you can get these modules installed properly.

You can do this under Debian with make-kpkg(1)
  1. apt-get source openafs-modules-source
  2. cd /usr/src
  3. tar xzf openafs.tar.gz
  4. cd /path/to/kernel/source
  5. make-kpkg modules_image
  6. dpkg -i ../openafs-modules*deb
The Debian Packages, at least, come with a script to do all this for you
afs-newcell

Set up the root volume:

There is also a script to to this
afs-rootvol