Instead of adding a new field that also requires deleting it
when it's not needed, simply reset the already-passed key and
let ceph-fs handle the rest.
This patchset implements key rotation for managers only. The user
can specified either the full entity name (i.e: 'mgr.XXXX') or
simply 'mgr', which stands for the local manager.
After the entity's directory is located, a new pending key is
generated, the keyring file is mutated to include the new key and
then replaced in situ. Lastly, the manager service is restarted.
Note that Ceph only has one active manager at a certain point,
so it only makes sense to call this action on _every_ mon unit.
A job name passed via the prometheus_scrape library doesn't end up as a
static job name in the prometheus configuration file in the COS world
even though COS expects a fixed string. Practically we cannot have a
static job name like job=ceph in any of the alert rules in COS since the
charms will convert the string "ceph" into:
Let's give up the possibility of the static job name and use "up{}" so
it will be annotated with the model name/ID, etc. without any specific
job related condition. It will break the alert rules when one unit have
more than one scraping endpoint because there will be no way to
distinguish multiple scraping jobs. Ceph MON only has one prometheus
endpoint for the time being so this change shouldn't cause an immediate
issue. Overall, it's not ideal but at least better than the current
status, which is an alert error out of the box.
The following alert rule:
> up{} == 0
will be converted and annotated as:
> up{juju_application="ceph-mon",juju_model="ceph",juju_model_uuid="UUID"} == 0
