Ceph » Orchestrator

if you have a service spec that does placement by explicit hosts such as

service_type: mon
service_name: mon
placement:
  hosts:
  - vm-00
  - vm-01
  - vm-02

and then you add the _no_schedule label to a host specified in the spec, the daemon won't be removed from the host. Instead you'll end up hitting

2022-07-29T18:32:23.854135+0000 mgr.vm-00.aezdbv [ERR] Failed to apply mon spec ServiceSpec.from_json(yaml.safe_load('''service_type: mon
service_name: mon
placement:
  hosts:
  - vm-00
  - vm-01
  - vm-02
''')): Cannot place <ServiceSpec for service_name=mon> on vm-02: Unknown hosts

I think the expected behavior here should be to remove the daemon from the host and the "Unknown hosts" error should be only for cases where the user specifies a host in their spec that is not managed by cephadm.