[Engineering] Changes to SWAT deployment policies, effective Monday April 30th

Thu Apr 26 22:14:59 UTC 2018

Hello,

I have made two changes to SWAT policies today.

First, we now disallow multi-sync patch deployments. See T187761[0].
This means that the sync order of files is determined by git commit
parent relationships (or Gerrit's "depends-on"). This is to prevent SWAT
deployers from accidentally syncing two patches in the wrong order.

Second, we are reducing the number of allowed patches from 8 to 4. This
is to reduce stress on the SWAT deployer as well as set expectations for
requesters on the pace of the windows. See the approximate best case
time spent breakdown[1] for how we came to this number.

I've updated the on-wiki documentation on wikitech[2][3].

Thank you for flying scap,

Greg

[0] https://phabricator.wikimedia.org/T187761
[1] 
* +2/Wait for Jenkins to merge - 2 min
* prepare git on tin - 1 min
* Deploy to mwdebug - 1 min
* Verify on mwdebug - 3 min
* Deploy to production - 1 min
* Verify & wait/watch logs - 2 min
[2] https://wikitech.wikimedia.org/w/index.php?title=SWAT_deploys&diff=prev&oldid=1789212
[3] https://wikitech.wikimedia.org/w/index.php?title=SWAT_deploys&diff=next&oldid=1789212

-- 
| Greg Grossmeier            GPG: B2FA 27B1 F7EB D327 6B8E |
| Release Team Manager            A18D 1138 8E47 FAC8 1C7D |