[gtirloni]

You will barely spend any time switching between one or the other. The tool doesn't matter.

Learn deeply how cgroups, namespaces, etc, work and transfer you knowledge about the building blocks to anything new that shows up.

[mattpallissard]

This. Understanding what the kernel does and the behaviors maps to any technology. What happens when you hit memory pressure? What causes it? What things are global or local to your cgroup?

Being able to answer questions like that transcends your container runtime. At that point it's just reading the docs, looking for the the label on the knob you already know needs tweaking.