Sidekiq refuse to start with no explicit error

[loic.c...@voxity.fr]

Hello,

Since my upgrade last week, from 8.7 to 8.8, using source installation, my sidekiq refuse to start, without any explicit message.
My server is running on the lastest ubuntu server with 2Go Ram.

If i try to check what is going wrong with sudo -u git -H bundle exec rake gitlab:sidekiq:check RAILS_ENV=production

this message is returned:

Checking Sidekiq ...

Running? ... no
  Try fixing it:
  sudo -u git -H RAILS_ENV=production bin/background_jobs start
  For more information see:
  doc/install/installation.md in section "Install Init Script"
  see log/sidekiq.log for possible errors
  Please fix the error above and rerun the checks.

Checking Sidekiq ... Finished

Next i run the given command, and run without any errors (but sidekiq does not work again). So as suggested, i try to find some errors on log/sidekiq.log, but not clear message except: "undefined method `delete' for nil:NilClass"

2016-06-08T16:43:19.277Z 2890 TID-gso49ojro INFO: Booting Sidekiq 4.1.2 with redis options {:url=>"unix:/var/run/redis/redis.sock", :namespace=>"resque:gitlab"}
undefined method `delete' for nil:NilClass
/home/git/gitlab/config/initializers/sidekiq.rb:16:in `block (2 levels) in <top (required)>'
/home/git/gitlab/config/initializers/sidekiq.rb:16:in `each'
/home/git/gitlab/config/initializers/sidekiq.rb:16:in `block in <top (required)>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-4.1.2/lib/sidekiq.rb:70:in `configure_server'
/home/git/gitlab/config/initializers/sidekiq.rb:1:in `<top (required)>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:268:in `load'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:268:in `block in load'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:268:in `load'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/engine.rb:652:in `block in load_config_initializer'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/notifications.rb:166:in `instrument'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/engine.rb:651:in `load_config_initializer'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/engine.rb:616:in `block (2 levels) in <class:Engine>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/engine.rb:615:in `each'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/engine.rb:615:in `block in <class:Engine>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:30:in `instance_exec'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:30:in `run'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:55:in `block in run_initializers'
/usr/local/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
/usr/local/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
/usr/local/lib/ruby/2.1.0/tsort.rb:418:in `block (2 levels) in each_strongly_connected_component_from'
/usr/local/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
/usr/local/lib/ruby/2.1.0/tsort.rb:417:in `block in each_strongly_connected_component_from'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:44:in `each'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:44:in `tsort_each_child'
/usr/local/lib/ruby/2.1.0/tsort.rb:411:in `call'
/usr/local/lib/ruby/2.1.0/tsort.rb:411:in `each_strongly_connected_component_from'
/usr/local/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component'
/usr/local/lib/ruby/2.1.0/tsort.rb:345:in `each'
/usr/local/lib/ruby/2.1.0/tsort.rb:345:in `call'
/usr/local/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component'
/usr/local/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
/usr/local/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:54:in `run_initializers'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/railties-4.2.6/lib/rails/application.rb:352:in `initialize!'
/home/git/gitlab/config/environment.rb:5:in `<top (required)>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-4.1.2/lib/sidekiq/cli.rb:234:in `boot_system'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-4.1.2/lib/sidekiq/cli.rb:50:in `run'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-4.1.2/bin/sidekiq:12:in `<top (required)>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/bin/sidekiq:23:in `load'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/bin/sidekiq:23:in `<top (required)>'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/cli/exec.rb:63:in `load'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/cli/exec.rb:63:in `kernel_load'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/cli/exec.rb:24:in `run'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/cli.rb:304:in `exec'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/vendor/thor/lib/thor/invocation.rb:126:in `invoke_command'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/vendor/thor/lib/thor.rb:359:in `dispatch'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/vendor/thor/lib/thor/base.rb:440:in `start'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/cli.rb:11:in `start'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/exe/bundle:27:in `block in <top (required)>'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/lib/bundler/friendly_errors.rb:98:in `with_friendly_errors'
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.3/exe/bundle:19:in `<top (required)>'
/usr/local/bin/bundle:23:in `load'
/usr/local/bin/bundle:23:in `<main>'

As i reed, sidekig can't find delete method.

Any librairies missing in my setup ? Bug found on gitlab source code ?

Thanks for your suggestion.
Regards.

[demisx]

Same error here on GitLab 8.8

[CK Poon]

Temp Solution: Comment whole section of cron_jobs in gitlab.yml would resolve the problems....