[Mongrel] problems with apache 2.2 proxying to mongrel cluster

Michael D'Auria michael.dauria at gmail.com
Tue Jan 2 17:51:31 EST 2007


I didn't know i could use the Logger class like that, pretty sweet.

Do people know if rotating the logs via Logger is the issue or just rotating
in general?

.: Michael :.


On 1/2/07, Michael Kovacs <kovacs at gmail.com> wrote:
>
> Hmm... thanks for the suggestion I'll give that a look as well as
> search the archives here.
>
> I do have the logger rotating daily right now:
> config.logger = Logger.new(config.log_path, 'daily')
>
> I think I'll remove that and see if this occurs again. The thing that
> still bothers me though
> is that if one mongrel is broken from this shouldn't they all be? I
> can always count on 1 of 4 mongrels
> working so that every 3rd request is successful :-) In order to
> monitor that I'd have to hit the site twice to
> ensure that I'm not just getting the good mongrel on the first hit.
> Not very fresh.
>
> -Michael
> http://javathehutt.blogspot.com
>
> On Jan 2, 2007, at 1:36 PM, Joey Geiger wrote:
>
> > This may have to do with log rotation. There was a thread about
> > similar issue posted in I believe December. You might want to try
> > searching the mailing list archives.
> >
> > You're probably rotating your logs based on a specific size, which is
> > why it's happening every couple hours, instead of nightly.
> >
> > On 1/2/07, Michael Kovacs <kovacs at gmail.com> wrote:
> >> Hi all,
> >>
> >> I've been having problems with the apache 2.2-mod_proxy_balancer-
> >> mongrel
> >> setup.
> >>
> >> My setup is:
> >>
> >> CentOS 4.3
> >> apache 2.2.3 (compiled from source) with mod_proxy_balancer
> >> mysql 4.1
> >> ruby 1.8.4
> >> mongrel 0.3.14 (I know I need to update but I think this problem is
> >> independent of the mongrel version)
> >> mongrel_cluster 0.2.0
> >> rails_machine 0.1.1
> >>
> >> I have apache setup as per Coda's configuration on his blog
> >> posting from
> >> several months back.
> >> http://blog.codahale.com/2006/06/19/time-for-a-grown-up-server-
> >> rails-mongrel-apache-capistrano-and-you/
> >>
> >> I have 4 mongrels in my cluster.
> >>
> >> Things work fine for periods of time but after several hours of
> >> inactivity
> >> (I think 8 hours or so) I experience oddness where only 1 of the 4
> >> mongrels
> >> is properly
> >> responding. I end up getting a "500 internal server error" 3 out of 4
> >> requests as they round robin from mongrel to mongrel. There is
> >> nothing in
> >> the production
> >> log file nor in the mongrel log. I've reproduced this problem on
> >> my staging
> >> box as well as my production box.
> >>
> >> The last time I reproduced the problem I decided to run "top" and
> >> see what's
> >> going on when I hit the server.
> >> Mongrel does receive every request but mysql is only active on the
> >> 1 request
> >> that works. In the other mongrels it never spikes up in CPU usage.
> >>
> >> Looking at the mysql process list revealed that all of the
> >> processes had
> >> received the "sleep" command but one of the processes is still
> >> working properly. I've played with connection timeouts other than
> >> to set the
> >> timeout in my application's environment
> >> (ActiveRecord::Base.verification_timeout = 14400) as well as the
> >> mysql
> >> interactive_timeout variable but it seems that all the mongrels
> >> should work
> >> or they shouldn't. The fact that 1 out of 4 always works is rather
> >> puzzling
> >> to me.
> >>
> >> Trying a 'killall -USR1 mongrel_rails" to turn debug on simply
> >> killed the 4
> >> threads running mongrel. So now I'm running the cluster in debug
> >> mode and am
> >> going to just let it sit there for several hours until it happens
> >> again and
> >> hopefully get some idea of where the breakdown is happening. I
> >> still think
> >> it has to be a mysql connection timeout but again, the fact that 1
> >> of the 4
> >> always works doesn't lend credence to the timeout theory.
> >>
> >> Has anyone experienced this phenomenon themselves?
> >>
> >> Thanks for any tips/pointers and thanks Zed for all your hard work
> >> with
> >> mongrel.
> >>
> >>
> >>
> >> -Michaelhttp://javathehutt.blogspot.com
> >>
> >>
> >> _______________________________________________
> >> Mongrel-users mailing list
> >> Mongrel-users at rubyforge.org
> >> http://rubyforge.org/mailman/listinfo/mongrel-users
> >>
> >>
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