Merge branch '40396-use-pgroups-for-background-jobs' into 'master'

bin/background_jobs: use pgroups

Closes #40396

See merge request gitlab-org/gitlab-ce!25654

bin/background_jobs

@@ -38,7 +38,14 @@ start_no_deamonize()
 
 start_sidekiq()
 {
-  exec bundle exec sidekiq -C "${sidekiq_config}" -e $RAILS_ENV -P $sidekiq_pidfile "$@"
+  cmd="exec"
+  chpst=$(which chpst)
+
+  if [ -n "$chpst" ]; then
+    cmd="${cmd} ${chpst} -P"
+  fi
+
+  ${cmd} bundle exec sidekiq -C "${sidekiq_config}" -e $RAILS_ENV -P $sidekiq_pidfile "$@"
 }
 
 load_ok()

changelogs/unreleased/40396-use-pgroups-for-background-jobs.yml

+---
+title: 'If chpst is available, make fron-source installations run sidekiq as a process group leader'
+merge_request: 25654
+author:
+type: other

doc/install/installation.md

@@ -9,7 +9,8 @@ On heavily used GitLab instances the memory usage of the Sidekiq background work
 
 Omnibus packages solve this by [letting the Sidekiq terminate gracefully](../administration/operations/sidekiq_memory_killer.md) if it uses too much memory.
 After this termination Runit will detect Sidekiq is not running and will start it.
-Since installations from source don't have Runit, Sidekiq can't be terminated and its memory usage will grow over time.
+Since installations from source don't use Runit for process supervision, Sidekiq
+can't be terminated and its memory usage will grow over time.
 
 ## Select Version to Install
 
@@ -72,7 +73,8 @@ Install the required packages (needed to compile Ruby and native extensions to R
 ```sh
 sudo apt-get install -y build-essential zlib1g-dev libyaml-dev libssl-dev libgdbm-dev libre2-dev \
   libreadline-dev libncurses5-dev libffi-dev curl openssh-server checkinstall libxml2-dev \
-  libxslt-dev libcurl4-openssl-dev libicu-dev logrotate rsync python-docutils pkg-config cmake
+  libxslt-dev libcurl4-openssl-dev libicu-dev logrotate rsync python-docutils pkg-config cmake \
+  runit
 ```
 
 Ubuntu 14.04 (Trusty Tahr) doesn't have the `libre2-dev` package available, but