Kubernetes volume-mounts with subPath and inotify. Bah humbug
So. I’ve been working on this tool ‘fluent-bit‘. You know the drill. Compile, curse, change, pull-request, repeat. And one of the features I added was to auto-watch its config file and restart on change. This is important in a Kubernetes environment since you supply config via a ‘config map’, and expect it to auto-apply. Great. Change made, unit test written, code sent.
But it doesn’t work in ‘the cloud’. Why? Well turns out there is a tiny caveat in Kubernetes…. ConfigMap subPaths don’t update. Huh? And, the helm chart for fluent-bit guess what, it uses a subPath for its ConfigMap.
Now I’ve ranted, you have read, and you will save yourself the time and aggravation I had in tracking this down.