This is part of the "Debug Containers" feature and is hidden behind
a feature gate. Debug containers have no stored spec, so this new
runtime label allows the kubelet to treat containers differently
without relying on spec.
Enforce the following limits:
12kb for total message length in container status
4kb for the termination message path file
2kb or 80 lines (whichever is shorter) from the log on error
Fallback to log output if the user requests it.