TIL that Kubernetes can give you a shell into a crashing container

When a container crashes, it can be for several reasons. Sometimes the log won't tell you much about why the container crashed, and you can't get a shell into that container because... it has already crashed. It turns out that kubectl debug can let you do exactly that. I was trying to ship Helfertool on our Kubernetes cluster. The firs step was to get it to work locally in my Minikube. The container I was deploying kept crashing, with an error message that put me on the right track: Cannot write to log directory. Exiting. The container expected me to mount a volume on /log so it could write logs, which I did. I wanted to run a quick test from within the container to see if I could create a file in that directory. But when your container has already crashed you can't get a shell into it. My better informed colleague Quentin told me about kubectl debug, a command that lets me create a copy of the crashing container but with a different COMMAND. So instead of running its normal program,…