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1. Current Authentication Scheme

1.1. Name Switch Server

Groups and users (passwd) come first from afs and then from files. This requires special trickery to ensure openafs starts before even the firewall.

We chose libnss-afs because there isn't really any point being able to query networked user and group information if openafs is not working since anything needing that info is going to rely on openafs anyway. Which is to say basically everything.

1.2. PAM

Using the standard Debian squeeze pam config framework, we have pam_krb5 and pam_afs_session enabled to permit Kerberos users to login. On admin nodes, login.restrict is used to only allow admins access.

2. Open Questions

Using libnss-afs is not without its disadvantages. We may want to use ldap again as the user directory for various reasons.

2.1. LDAP



2.2. AFS PTS Server



3. Old Authentication Scheme

This is how things are done on deleuze, mire, and hopper (hopper at least should be changed).

Regarding the exact authentication mechanism on HCoop. Each machine is unconditionally configured in one of the modes:

  1. No user logins are allowed
  2. User logins allowed, go through Kerberos and AFS
  3. User logins allowed, go through local Unix authentication, on local disk

All login configuration is done through PAM (/etc/pam.d/* files).

If /etc/login.restrict file is present, it automatically limits logins only to accounts listed in the file.

Speaking of Kerberos login, it's useful to mention/remind ourselves of the ~/.k5login feature (see manpage). We don't rely on this anywhere, but as said, useful to know about.


AuthenticationScheme (last edited 2013-01-11 08:39:38 by ClintonEbadi)