Configuration of AFS client for access to cern.ch
(OpenAFS on Ubuntu 10.10)

Install packages:

  $ sudo apt-get install openafs-client openafs-modules-dkms openafs-krb5 krb5-user krb5-config

Configure AFS client and Kerberos:

1. use "cern.ch" as default AFS cell:
  
    $ echo "cern.ch" | sudo tee /etc/openafs/ThisCell

2. setup kerberos5 authentication:
  add following lines to file '/etc/krb5.conf':
  
==========================================>

# settings for CERN.CH realm are taken from file
#   lxplus.cern.ch:/etc/krb5.conf

[libdefaults]
  default_realm = CERN.CH

[realms]
  CERN.CH = {
    default_domain = cern.ch
    kpasswd_server = cerndc.cern.ch
    admin_server = cerndc.cern.ch
    kdc = cerndc.cern.ch
  }

[domain_realm]
  cern.ch = CERN.CH
  .cern.ch = CERN.CH

<=========================================

3. re-start OpenAFS client:
  
  $ sudo service openafs-client restart


4. login (optional, only needed to access protected paths):

  $ kinit user@CERN.CH     # get kerberos ticket
  $ aklog                  # login to AFS cell

5. work with files:

  $ ls -l /afs/cern.ch/sw/lcg/external


Etc:

Configuration steps 1) and 2) can be done with:
  $ sudo dpkg-reconfigure openafs-client
  $ sudo dpkg-reconfigure krb5-config


References:

  http://blogs.interdose.com/sebastian/2010/01/31/openafs-client-on-ubuntu-9-10-%E2%80%9Ckarmic-koala%E2%80%9D/
  http://matienzo.org/project/setting-up-umich-afs-on-ubuntu
  http://freecog.net/2007/openafs-ubuntu-feisty