University Computing Systems
Long-running jobs
- Upon login to an AFS machine, a user is automatically granted a "token"
by the Kerberos authentication system. This token allows the user access to
directories in AFS where that user is explicitly allowed access, such as the
user's login directory tree. Without a token, a user is in the category
"system:anyuser" (anonymous), and has access only to those directories
where system:anyuser is explicitly given access rights.
- Tokens are on a per-machine basis: i.e., a user's tokens on machine-A
and machine-B are not related
- To check token status: /usr/afsws/bin/tokens
- Tokens man page: man tokens (/usr/afsws/man/man1/tokens.1 on
afs1.njit.edu - afs36.njit.edu)
- The default token lifetime is 25 hours; to request a longer token
lifetime, up to 500 hours, send mail to sys@oak.njit.edu
- If your executing program is reading or writing files, you will
need to make sure that your Kerberos token does not expire before your
job ends. The best way to do this is to log in to to the machine on which
your job is running often enough so that the expiration time of your
token is later than the expected finish time of your job.
- Your processes on a given machine will inherit whatever the current
expiration time of your token is. Upon logout, your processes will retain
your token expiration time as of immediately before logout.