opened
smarterclayton
username_0
Kubelet cert rotation involves two certificate manager instances
(one for client and one for server certs) and the log lines are
identical and confusing. Since certificate manager is a utility
library it is also inappropriate to simply assume klog output is
sufficient.

certificate.Manager now accepts a Name and Logf function on its
config struct to identify the purpose of the manager and to
provide a way to redirect where output should go. If Name is
absent, the name is defaulted from the SignerName, and if that
is not found then the name is set to "client auth" if that is
a provided key usage, or "certificate" otherwise. If Logf is
not provided it defaults to klog.V(2). as today. The name is printed
in "foo: bar" form on every line, but can be converted to structured
logging in the future. The log level is not customizable and it
is up to the caller to decide whether that is an issue.

Some log messages are slightly cleaned up to more clearly indicate
their intent. One log message is removed in a utility function that
was already at v(4) and less likely to be needed.

The default behavior of the certificate manager is as before and
the kubelet now identifies the server and client signerName as
separate entities:

I0414 19:07:33.590419    1539 certificate_manager.go:263] kubernetes.io/kube-apiserver-client-kubelet: Rotating certificates
E0414 19:07:33.594154    1539 certificate_manager.go:464] kubernetes.io/kube-apiserver-client-kubelet: Failed while requesting a signed certificate from the master: cannot create certificate signing request: Post "https://...

/kind bug
/kind cleanup

```release-note
The kubelet now reports distinguishes log messages about certificate rotation for its client cert and server cert separately to make debugging problems with one or the other easier.
```

```docs

```
Add type logging to certificate manager
issue
created
smarterclayton
username_0
will sort out the unit panic
comment
created
fedebongio
username_1
/assign @deads2k 
/triage accepted
comment
created
smarterclayton
username_0
panic was sorted, more reviews please
comment
created
mikedanese
username_2
/lgtm
comment