This change enables hot reload of encryption config file when api server
flag --encryption-provider-config-automatic-reload is set to true. This
allows the user to change the encryption config file without restarting
kube-apiserver. The change is detected by polling the file and is done
by using fsnotify watcher. When file is updated it's process to generate
new set of transformers and close the old ones.
Signed-off-by: Nilekh Chaudhari <1626598+nilekhc@users.noreply.github.com>
This change adds a flag --encryption-provider-config-automatic-reload
which will be used to drive automatic reloading of the encryption
config at runtime. While this flag is set to true, or when KMS v2
plugins are used without KMS v1 plugins, the /healthz endpoints
associated with said plugins are collapsed into a single endpoint at
/healthz/kms-providers - in this state, it is not possible to
configure exclusions for specific KMS providers while including the
remaining ones - ex: using /readyz?exclude=kms-provider-1 to exclude
a particular KMS is not possible. This single healthz check handles
checking all configured KMS providers. When reloading is enabled
but no KMS providers are configured, it is a no-op.
k8s.io/apiserver does not support dynamic addition and removal of
healthz checks at runtime. Reloading will instead have a single
static healthz check and swap the underlying implementation at
runtime when a config change occurs.
Signed-off-by: Monis Khan <mok@microsoft.com>
