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From: Eric Wong <normalperson@yhbt.net>
To: unicorn list <mongrel-unicorn@rubyforge.org>
Subject: Re: Issues with PID file renaming
Date: Thu, 12 Dec 2013 20:51:12 +0000	[thread overview]
Message-ID: <20131212205112.GA16284@dcvr.yhbt.net> (raw)
In-Reply-To: <52AA0B65.3050406@gentoo.org>

Petteri Räty <betelgeuse@gentoo.org> wrote:
> On 11.12.2013 15.54, Michael Fischer wrote:
> > On Tue, Dec 10, 2013 at 10:44 PM, Petteri Räty <betelgeuse@gentoo.org> wrote:
> > 
> >> At least for pid based monitoring tools it is (I do agree with others
> >> that you should also be monitoring http though). For example monit
> >> requires that you give it a pid file. Why is it wrong for them to point
> >> to the same pid?
> > 
> > Monit doesn't require a pid, never has:
> > 
> > http://mmonit.com/monit/documentation/monit.html#connection_testing
> > 
> 
> If you only want to do connection testing. What if you want to monitor
> the memory usage of unicorn processes?

Your monitoring has to adapt to the new processes anyways.  Can it
really not deal with a PID file being temporarily absent?

There's a plethora of tools in the wild which deal with PID files.
Consider this case:

It's likely a tool will see foo.pid.oldbin existing, and wait for
foo.pid to become available.  If foo.pid is already available from a
hardlink, it'll be pointing to the old PID, and any tool which backs out
of the upgrade by intending to kill the new PID will end up hitting the
old one.
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  reply	other threads:[~2013-12-12 20:51 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-26  1:00 Issues with PID file renaming Jimmy Soho
2013-11-26  1:20 ` Eric Wong
2013-11-26  1:40   ` Michael Fischer
2013-11-26  2:07     ` Eric Wong
2013-12-10 12:46   ` Petteri Räty
2013-12-10 19:52     ` Eric Wong
2013-12-10 22:44       ` Petteri Räty
2013-12-11 13:54         ` Michael Fischer
2013-12-12 19:15           ` Petteri Räty
2013-12-12 20:51             ` Eric Wong [this message]
2013-11-26  1:42 ` Michael Fischer
2013-11-26  4:55   ` Jimmy Soho

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