Petteri Räty <[email protected]> wrote: > 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?
No, every config option makes the project more difficult to support. > Can you say if lib/unicorn/http_server.rb:196 is the correct spot? Yes. > 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. Then, doesn't nginx have the same problem? > > 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. Is matching nginx rename behavior enough to solve the problem? Matching nginx behavior can become the default if it solves your problem. _______________________________________________ Unicorn mailing list - [email protected] http://rubyforge.org/mailman/listinfo/mongrel-unicorn Do not quote signatures (like this one) or top post when replying
