Failover scripts

Hello World,

I'm preparing to build a two-machine master-slave set-up for Apache SVN
(linux, svnsync mirroring to slave, no cluster). Now, I remember seeing in
the past scripts tailored to this kind of architecture, alas I cannot find
them anymore and not for a lack of googling.

Those included:
- scripts that automagically promote slave to master in case master is down,
- scripts that would edit (replace) post-commit hooks in the above case and
the Apache config.

In case of failover some cleanup is assumed on part of the slave:
unfinished syncs and change of its hooks.Redirecting the users would be
done via loadbalancer that checks for the availability of master the same
way slave does.

Two points on which I am really vague:

- What if the master thinks it is still active and has means to access the
slave. Can we prevent this somehow with hook scripts by blocking the sync
user?
- Switch back after a failover without downtime - possible? Or leave the
slave as master (which makes the excahnge of config and hooks a tad
complicated)?

I could really use your insight and if anyone has experience with this kind
of set-up please shed some light on the subject.
Received on 2014-02-21 09:15:06 CET