Is it possible to restart Unicorn without downtime?

sam · June 27, 2017, 12:45am

Sort of, we do:

lib/docker_manager/upgrader.rb

main


      
          
          percent(80)
          web_server.reload
          reloaded = true
          
          # Flush nginx cache here - this is not critical, and the rake task may not exist yet - ignore failures here.
          percent(85)
          begin
            run("bundle exec rake assets:flush_sw")
          rescue RuntimeError
            log "WARNING: Unable to flush service worker file"
          end
          
          percent(90)
          log("Running post deploy migrations")
          run("bundle exec rake multisite:migrate")
          
          run("bundle exec rake s3:expire_missing_assets") if using_s3_assets
          
          log_version_upgrade
          percent(100)

So you would send the USR2 to the unicorn launcher that will forward the signal for you.

github.com/discourse/docker_manager

lib/docker_manager/upgrader.rb

main


      
          end
          
          def reset!
            @repos.each(&:stop_upgrading)
            clear_logs
            percent(0)
            status(nil)
          end
          
          def upgrade
            return if @repos.any? { |repo| !repo.start_upgrading }
          
            percent(0)
            status("running")
          
            clear_logs
          
            log("********************************************************")
            log("*** Please be patient, next steps might take a while ***")
            log("********************************************************")

Topic		Replies	Views
Sv hup unicorn dropping traffic Product Support	2	152	September 1, 2026
Too many unicorn workers - failed to stop for upgrade? Self-hosting	4	973	November 3, 2020
Browser upgrade fails when discourse is configured to use one unicorn worker Bug	5	545	October 18, 2023
Upgrade abort - not enough Unicorn workers running Self-hosting	4	210	January 8, 2026
"Waiting for unicorn to reload", then update stops Product Support	30	5142	June 20, 2021

Is it possible to restart Unicorn without downtime?

Related topics