Replace the usage of the deprecated wait.Poll() and
wait.PollImmediate() functions with wait.PollUntilContextTimeout().
Since we don't have piping of context around kubeadm,
use context.Background() everywhere.
Some wait.Poll() functions were converted to "immediate" as there
is no point for them to not be. This is done for consistency.
Replace the only instance of wait.JitterUntil with
wait.PollUntilContextTimeout. JitterUntil is not deprecated
but this is also done for consistency.
For file discovery, in case the user feeds a file for the CA
from the kubeconfig, make sure it's preloaded and embedded using
the new function EnsureCertificateAuthorityIsEmbedded().
This commit also applies cleanup:
- unroll validateKubeConfig() into ValidateConfigInfo() as this way
the default cluster can be re-used.
- in ValidateConfigInfo() reuse the variable config instead of creating
a new variable kubeconfig.
- make the Ensure* functions return descriptive errors instead of
wrapping the errors on the side of the callers.
- move most unrelated to phases output to klog.V(1)
- rename some prefixes for consistency - e.g.
[kubelet] -> [kubelet-start]
- control-plane-prepare: print details for each generated CP
component manifest.
- uppercase the info text for all "[reset].." lines
- modify the text for one line in reset
