On 26.11.2012 2.43, Eric Wong wrote: > Petteri Räty <[email protected]> wrote: >> What follows are all the write actions related to unicorn pid file when >> doing a hot restart. Seems like a bug to me that unicorn is deleting the >> pid file before writing the new file. Is there a reason for it? It seems >> to go against that rename that aims for an atomic replace that would >> always ensure the pid file is there. > > Unfortunately, pid files are inherently racy. However, I > seem to recall a pid file not existing for a brief moment was needed > to allow some nginx-based scripts to work. >
Would you be open for a config switch to avoid this behavior? Can you say if lib/unicorn/http_server.rb:196 is the correct spot? The use case here is that with health monitors wouldn't have a window where a pid file does not exist. With a hot restart it should always be possible to have a pid file that points to either the old or the new master. > I think unicorn differs a bit from nginx here: > > nginx uses rename() to clear the way for a new pid file. Like unicorn, > this still leaves a window where no pid file exists. > Looking at the inotify log it seems the reason pid file does not exist is an explicit delete and not due to rename. It happens a couple seconds earlier also so the window is possible to hit even with a periodic poller. Regards, Petteri _______________________________________________ Unicorn mailing list - [email protected] http://rubyforge.org/mailman/listinfo/mongrel-unicorn Do not quote signatures (like this one) or top post when replying
