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2022-05-25: Gitaly is leaking git-cat-file processes

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Roles when the incident was declared:

Current Status

Gitaly is leaking git-cat-file(1) processes which aren't getting cleaned up as expected. This leads to hundreds of Git processes sticking around until Gitaly is restarted, and each of these processes can easily consume a few gigabytes of memory. Ultimately, this may lead to resource exhaustion when too many processes have built up. This incident seems to have been ongoing for several weeks already, but was first discovered as part of #7107 (closed). Until now, we haven't seen major issues mostly because Gitaly is frequently restarted during deployments, which cleans up the Git processes.

The Gitaly issue is tracked via gitlab-org/gitaly#4253 (closed). An initial investigation surfaced a deadlock in Gitaly, which was fixed via gitlab-org/gitaly!4581 (merged). Unfortunately, this fix didn't seem to affect the leaking processes as observed in production.

More information will be added as we investigate the issue. For customers believed to be affected by this incident, please subscribe to this issue or monitor our status page for further updates.

Summary for CMOC notice / Exec summary:

  1. Customer Impact: Machines become increasingly more starved on resources, most importantly memory. Ultimately, this can lead to an increase an Git spawn failures and thus general increase in errors on Gitaly nodes.
  2. Service Impact: ServiceGitaly
  3. Impact Duration: unclear, has been ongoing for more than a week - end time UTC ( duration in minutes )
  4. Root cause: TBD

Timeline

Recent Events (available internally only):

All times UTC.

2022-05-23

  • 03:40 - #7107 (closed) is declared, which is the first time this has knowingly caused problems.
  • 03:48 - Incident resolves because Gitaly nodes have been restarted.
  • 06:49 - It is discovered that we have gradual build-up of Git commands. #7107 (comment 956011382)

2022-05-24

2022-05-25

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Edited by Patrick Steinhardt