Confused about restart/upgrade w. bundler and symlinks

Eric Wong normalperson at
Wed Oct 23 16:02:08 UTC 2013

Carlos Peñas <theistian at> wrote:
> Hi.
> I'm having an issue using unicorn with bundler on a rails ap deployed by
> capistrano
> Im using bundler 1.3.5 (tried 1.4rc0 also) I'm deploying with
> capistrano, version is irrelevant, the issue hit me when keep releases
> is reached and 'current' symlink where "bundle unicorn" process was
> initially started.
> Im using also unicorn 4.6.3 and ruby 2.0.0, it is a Rails 4 app runing
> on linux 3.2 64
> I'm restarting with a init.d script which sends a HUP to master (restart) or USR2 (upgrade)
> bundled gems are vendorized and stored in a shared location between
> deploys. pids and logs also.
> In the config have lines for:
> Unicorn::HttpServer::START_CTX[0] pointing to the binary in the bundle

Actually, I'm not 100% sure if that's correct
I'll let somebody who uses bundler correct me, but you *might* need
 to use something like this instead:

  start_ctx = Unicorn::HttpServer::START_CTX
  start_ctx[0] = "bundle"
  start_ctx[:argv] = %w(exec unicorn).concat(start_ctx[:argv])

> and ENV["BUNDLE_GEMFILE"] pointing to "current" path of the gemfile

> When a capistrano deploy reach the :keep_releases and deletes a release
> directory where unicorn was previously started the master kills all the
> workers an the new worker get in a death loop telling that they can not
> locate 'rack/builder'.

Wait, this means you've had multiple deploys fail to reach :keep_releases
and have it delete directories?  Might not be easy to recover from...

Can you check the output of:

	tr '\0' '\n' < /proc/$PID/environ

On the killing master process for anything that looks like GEM/PATH/RUBY?
Perhaps something is out-of-date in one of those paths and not
unset/reset correctly by bundler.

> I traced the process and the diying worker threads are looking for files
> in the deleted release directory.
> Problem is crystal clear to me. Unix dereferences 'current' directory
> and store it in the proc environment so when the referenced directory
> dissapear unicorn workers aren't able to locate cwd. But I can't find a
> workarround which let me use a deploy tool and bundle to keep project
> gems.
> So What i'm missing? is there a best practice I'm not following?.

Are you setting working_directory in your config file?
That might fix some things up.  Can you also ask some bundler
users/developers for assistance?

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