AO3-6890 Add puma worker killer gem

[brianjaustin]

https://otwarchive.atlassian.net/browse/AO3-6890

[Bilka2]

Based on the docs I think you might have to call PumaWorkerKiller.enable_rolling_restart somewhere (which would also have a built-in splay). zombocom/puma_worker_killer#4 / https://github.com/zombocom/puma_worker_killer?tab=readme-ov-file#attention also suggest not putting it in an initializer for rails (and putting into before_fork), not sure if that still applies these days (maybe you know better how Puma is started in staging/production)

[redsummernight]

Do we need a before_fork hook, or a call to start? Would the gem be activated this way?

[brianjaustin]

Yeah I'm pretty sure Bilka is right. Based on the docs (which I am having a little trouble following since there seem to be multiple paths to configuring it), we need to do this in Ansible instead. The linked PR (visible only to folks with read+ access to that repo) needs to do it instead, since we don't have config/puma.rb here

[zz9pzza]

I was expecting to do it in the config/puma.rb

[brianjaustin]

Yes, I removed this file and moved it to Ansible's config/puma.rb in https://github.com/OTWSystems/ansible/pull/146