Adding a label to a host

Use the Ceph Orchestrator to add a label to a host. Labels can be used to specify placement of daemons.

A few examples of labels are mgr, mon, and osd based on the service deployed on the hosts. Each host can have multiple labels.

You can also add the following host labels that have special meaning to cephadm and they begin with _:

• _no_schedule: This label prevents cephadm from scheduling or deploying daemons on the host. If it is added to an existing host that already contains Ceph daemons, it causes cephadm to move those daemons elsewhere, except OSDs which are not removed automatically. When a host is added with the _no_schedule label, no daemons are deployed on it. When the daemons are drained before the host is removed, the _no_schedule label is set on that host.

• _no_autotune_memory: This label does not autotune memory on the host. It prevents the daemon memory from being tuned even when the osd_memory_target_autotune option or other similar options are enabled for one or more daemons on that host.

• _admin: By default, the _admin label is applied to the bootstrapped host in the storage cluster and the client.admin key is set to be distributed to that host with the ceph orch client-keyring {ls|set|rm} function. Adding this label to additional hosts normally causes cephadm to deploy configuration and keyring files in the /etc/ceph directory.