www-gitlab-com unaccessible

At 09:28 UTC we noticed that gitlab-com/www-gitlab-com was unavailable. A quick investigation found out that the cache that rails uses was corrupt. We quickly fixed this by manually expiring the cache and at 10:26 the repository went back online.

To-do's:

• Check if other repositories are experiencing the same issue and expire the caches for all of them.
• Write a runbook that explains how to perform the manual expiration in case of necessity.

Questions:

• Why did the cache get corrupt?
• How can we avoid this from happening again in the future?
• How can we monitor this?
• Who is the point of contact for this kind of issue?