[rancid] Repetitive RANCID Checks

[heasley]

Thu, May 15, 2014 at 04:44:46PM +0200, Alan McKinnon:
> I see what the bug is here, the solution probably needs list discussion
> first.
> 
> With rancid-2.3.8 and perl-5.18, ipv6 prefix-lists are always output in
> random order if ACLSORT=yes
> 
> The cause is twofold:
> 
> 1. "sub ipaddrval" is ipv4-specific and cannot deal with ipv6 addresses
> properly, so sortbyipaddr() doesn't work as intended. I believe that
> %history in ProcessHistory() is not being sorted at all
> 
> 2. A recent perl version re-implemented hashes to guarantee that keys
> are randomly ordered internally and different between runs of the same
> script. The previous implementation would order the same data
> consistently between invocations.

bugger.  thanks for that.  another user was asking about this problem and
i was having trouble recreating it.

> So ipv6 prefix-list ordering just happened to work with <perl-5.18
> because %history just happened to be consistently ordered.
> 
> Solutions:
> 
> 1. Implement ipv6 sorting in sortbyipaddr(). I really want to find an
> excuse not to do this (being essentially a lazy bum at heart)
> 
> 2. Why are we sorting these lists by ip address? Surely sorting 1) by
> prefix name then 2) by seq makes more sense? This is what my NetOps
> colleagues would like to see happen.

the sequences just tend to create noise, esp. when the whole list is
reloaded (therefore renumbered), and hides the actual change or makes it
less obvious.