Centralize our servers' logs

Right now we have volatile Journal + some persistent log files managed by rsyslog and individual applications. This sometimes makes it painful to debug problems since one has to cross-match info from various sources. It would be nicer if all our logs landed in a single place.

An initial idea to start brainstorming about it would be:

• on each of our systems, send all logs to journald
• configure these journalds to have volatile storage only (that’s the default and what we currently do) and to forward them to a single journald instance running in a central place
• in the central logging location, either have journald store logs in a persistent manner, or forward them to a fancy system like Graylog (that seems much easier to setup than an ELK stack)

Original created by @intrigeri on 11880 (Redmine)