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Tags

(2026-08-26)

CVS uses tags. Rancid uses CVS. Using this in combination with frequent configuration checkpointing we can look at diffs with respect to a baseline that is constant without having to worry what the revision number(s) of that/those file(s) is/are.

The way I do it is that I have a rancid configured to run using my home directory instead of the system directories, that way all the logins and changes in the audit system are associated to me, and the main repository is not poluted with a million interum versions that nobody is ever going to care about.

  1. Update rancid and then tag the rev you want to keep:
export CVSROOT=/home/david/rancid/CVS
rancid-run
cvs tag checkpoint

Note that this tags the repository from the directory you're in down, but not up.

So if I'm in /home/david/rancid/switchset/configs, the tag command will tag the switch versions in configs, but not tag ../router.db and friends. If the router.db etc is important then you hav to run the tag command from the switchset directory. Or specify it explicitly in the command.

  1. Workie workie, and then update the config again:
[...]
rancid-run
[...]
rancid-run]
  1. Check diff against the fixed baseline:
cvs diff -r checkpoint
  1. Later you might want to know what the tags on the repository are.

Run cvs headand look at the Symbolic Names section:

[...]
RCS file: /home/david/rancid/CVS/switchset/router.db,v
Working file: router.db
head: 1.3
branch:
locks: strict
access list:
symbolic names:
        checkpoint: 1.1
keyword substitution: kv
total revisions: 3
[...]
  1. And if you want to remove the tag from the repository:
cvs tag -d checkpoint
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