A brief maintenance accident turns for the worse as GitHub's database automatically fails over and breaks the website.

Sources:
https://github.blog/20181030oct21...
https://github.blog/20161208orches...
https://github.blog/20180620mysql...
https://news.ycombinator.com/item?id=...
  / github_major_service_outage  
https://hub.packtpub.com/githubdown...
https://github.blog/20171012evolut...

Chapters:
0:00 Part 1: Intro
1:25 Part 2: GitHub's database explained
3:40 Part 3: The 43 seconds
5:04 Part 4: Fail back or not?
6:54 Part 5: Recovery process
10:32 Part 6: Aftermath

Notes:
Funnily enough in this blog post from 4 months prior to the incident https://github.blog/20180620mysql... they specifically explained how crossdatacenter failovers could be carried out successfully

Music:
Hitman by Kevin MacLeod
Blue Mood by Robert Munzinger
Pixelland by Kevin MacLeod
Dumb as a Box by Dan Lebowitz