Are there more docs related to https://docs.gradle.org/current/userguide/gradle_daemon.html#continuous_integration available? There appears to be no examples, recommendations, best practices etc. How many builds before we should consider retiring a build box? Should we git clean before git fetch? Should it run on bare metal, a vm, or a container? Should the box have swap? AWS EBS, or attached NMVe? Should we still use the remote build cache node, or is local cache strictly superior?

The part you linked to is solely about the Daemon usage. More information about CI is for example available in the Community Cookbook at https://cookbook.gradle.org/ci/. But most of your questions really depend on your builds and usage, so the answers would probably differ from case to case. 🤷‍♂️

Unfortunately https://cookbook.gradle.org/ci/gitlab-ci/#enable-caching doesn't have anything to say about the Gradle daemon

The link you initially provided already told you to use the daemon on CI, didn't it? Why should the cookbook repeat?

Well it simply mentions "using the Daemon", but not how to use. Should we design out CI to re-use daemons, or shut them down at the end of each build? It feels like I have more questions than the docs answer

That sentence is afair from times where

--no-deamon

really meant not to use a daemon. Nowadays even

--no-daemon

almost always uses a daemon, just a one-off one that is quit after one build. So that sentence with pretty high probability recommends to reuse the daemon which also is the default.

👍 for sure we don't do our builds

--no-daemon

. Currently I'm looking into making our CI builds perform a bit closer to developer machines, where i.e. we already have a warmed up daemon, with all dependencies downloaded. Looking for resources.