logrus doesn't support trace level. However, in general it's useful:

sirupsen/logrus#463 (comment)

@cretz I agree with you. In Kubernetes, we usually have:

• One log level for normal production log output (corresponds to logrus info)
• One log level for test environment output (corresponds to logrus debug)
• One log level for actual debug, we don't want to log this in test environment, because they are too spammy. But we do want to be able to turn on those logs when we actually see a problem and try to debug. (corresponds to what? I think this is where trace is useful.)

In #547, we added the trace level in our own log package.

However, since in the future, we'll use the log context containerd passes to us, we may want to support trace in containerd, too.