This task was originally meant only to remove nutcracker from the MediaWiki's config, but why not be bold and expand its scope!
Nutcracker is currently used in the following:
[ ] MediaWiki's config - its only usage is for wikitech
[ ] Thumbor
The configuration on app/api appservers for memcached has been removed with https://gerrit.wikimedia.org/r/#/c/operations/puppet/+/510697, and it will get applied upon the next round of reboots (so nutcracker will restart without impacting the session handling in Redis). We have tested the change in canaries and nothing weird has been noticed/reported/found.
The idea for this task is to migrate tools using nutcracker to mcrouter (if possible) to avoid maintaining in the long run two code bases (the nutcracker's one is basically abandoned).