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Neil wrote:
you have a virtual ip which only one of the hosts has at a time. I'd use that
have the cron job on both but making it check if its host has that ip address
and exit if it doesn't.
That's essentially the same mechanism I use to handle failover on a pair
of AIX boxes at work. In that case, all our application data is on a
shared SAN that both servers can mount, but only one at a time (by the
live system). In my cron jobs, I do something like:
00 01 * * * if [ -f /file/on/shared/filesystem ]; then /command/to/run; fi
so that /command/to/run will only get executed if
/file/on/shared/filesystem exists. It works quite well. You could
replace that conditional with something that checks for the existence of
your VIP interface, or anything else that is guaranteed to only exist on
the live box. The command being run doesn't have to know anything about
what's happening, since the failover check is being done within cron.
Dan Brown wrote:
My pair of LVS servers share the same database. I have a couple of sites
which import data daily from other sites, or via uploaded files. I do not
want the servers to both be running the same job at the same time obviously
so I'd like to swap out crontab files when the backup director takes over.
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