41 lines
2.2 KiB
Markdown
41 lines
2.2 KiB
Markdown
|
# Sidekiq MemoryKiller
|
||
|
|
|
||
|
|
The GitLab Rails application code suffers from memory leaks. For web requests
|
||
|
|
this problem is made manageable using
|
||
|
|
[unicorn-worker-killer](https://github.com/kzk/unicorn-worker-killer) which
|
||
|
|
restarts Unicorn worker processes in between requests when needed. The Sidekiq
|
||
|
|
MemoryKiller applies the same approach to the Sidekiq processes used by GitLab
|
||
|
|
to process background jobs.
|
||
|
|
|
||
|
|
Unlike unicorn-worker-killer, which is enabled by default for all GitLab
|
||
|
|
installations since GitLab 6.4, the Sidekiq MemoryKiller is enabled by default
|
||
|
|
_only_ for Omnibus packages. The reason for this is that the MemoryKiller
|
||
|
|
relies on Runit to restart Sidekiq after a memory-induced shutdown and GitLab
|
||
|
|
installations from source do not all use Runit or an equivalent.
|
||
|
|
|
||
|
|
With the default settings, the MemoryKiller will cause a Sidekiq restart no
|
||
|
|
more often than once every 15 minutes, with the restart causing about one
|
||
|
|
minute of delay for incoming background jobs.
|
||
|
|
|
||
|
|
## Configuring the MemoryKiller
|
||
|
|
|
||
|
|
The MemoryKiller is controlled using environment variables.
|
||
|
|
|
||
|
|
- `SIDEKIQ_MEMORY_KILLER_MAX_RSS`: if this variable is set, and its value is
|
||
|
|
greater than 0, then after each Sidekiq job, the MemoryKiller will check the
|
||
|
|
RSS of the Sidekiq process that executed the job. If the RSS of the Sidekiq
|
||
|
|
process (expressed in kilobytes) exceeds SIDEKIQ_MEMORY_KILLER_MAX_RSS, a
|
||
|
|
delayed shutdown is triggered. The default value for Omnibus packages is set
|
||
|
|
[in the omnibus-gitlab
|
||
|
|
repository](https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/files/gitlab-cookbooks/gitlab/attributes/default.rb).
|
||
|
|
- `SIDEKIQ_MEMORY_KILLER_GRACE_TIME`: defaults 900 seconds (15 minutes). When
|
||
|
|
a shutdown is triggered, the Sidekiq process will keep working normally for
|
||
|
|
another 15 minutes.
|
||
|
|
- `SIDEKIQ_MEMORY_KILLER_SHUTDOWN_WAIT`: defaults to 30 seconds. When the grace
|
||
|
|
time has expired, the MemoryKiller tells Sidekiq to stop accepting new jobs.
|
||
|
|
Existing jobs get 30 seconds to finish. After that, the MemoryKiller tells
|
||
|
|
Sidekiq to shut down, and an external supervision mechanism (e.g. Runit) must
|
||
|
|
restart Sidekiq.
|
||
|
|
- `SIDEKIQ_MEMORY_KILLER_SHUTDOWN_SIGNAL`: defaults to `SIGKILL`. The name of
|
||
|
|
the final signal sent to the Sidekiq process when we want it to shut down.
|