[Mailman-Users] Multi-Server install
Stephen J. Turnbull
turnbull.stephen.fw at u.tsukuba.ac.jp
Tue Aug 28 03:59:05 EDT 2018
First let me apologize on behalf of the project for the delay in
distribution of your post. It appears a few posts got trapped in
limbo for about 10 days, and the delay was definitely between
Mailman's MTA and mine.
> I inherited a mult-server install of Mailman.
> During a recent upgrade of the servers, I'm realizing the
> master-qrunner.pid file is in the 'data' directory which is shared
> between the two servers.
What version is Mailman? I believe that recent versions put the PID
file in the 'lock' directory.
On my Debian installation, that directory is /var/lib/mailman/lock,
which is actually a symlink to /var/lock/mailman. I suspect this
setup is intended to resolve exactly this kind of issue.
> I have the lock file set to use the hostname in the name of the lock file.
> Shouldn't the PID file be in a local directory?
Yes. You don't want the operation of local processes to be subject to
> the old servers had a cron entry to re-start mailman every night. I'm
> wondering if there was flakiness with a shared PID file going on that was
> 'fixed' by rebooting mailman nightly.
If the name of the host is in the name of the lock file, this should
not cause "flakiness" problems because a conflict between the systems.
However, in my Debian install, I have both master-qrunner and
master-qrunner.<host>.<pid>, hardlinked to the same file which
contains the full pathname (in /var/lib/mailman/lock).
I think it's more likely that either the whole system including the
network was flaky, or that Mailman isn't designed to be robust in a
multi-host configuration. It's generally designed to be robust
against various failures, so it's probably OK, but "multihost
operation with shared filesystem" was not an explicit design
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