Setting up the admin node

Use an admin node to administer the storage cluster.

An admin node contains both the cluster configuration file and the admin keyring. Both of these files are stored in the directory /etc/ceph and use the name of the storage cluster as a prefix.

For example, the default ceph cluster name is ceph. In a cluster using the default name, the admin keyring is named /etc/ceph/ceph.client.admin.keyring. The corresponding cluster configuration file is named /etc/ceph/ceph.conf.

To set up additional hosts in the storage cluster as admin nodes, apply the _admin label to the host you want to designate as an administrator node.

Note: By default, after applying the _admin label to a node, cephadm copies the ceph.conf and client.admin keyring files to that node. The _admin label is automatically applied to the bootstrap node unless the --skip-admin-label option was specified with the cephadm bootstrap command.

Prerequisites

A running storage cluster with cephadm installed.
The storage cluster has running Monitor and Manager nodes.
Root-level access to all nodes in the cluster.

Procedure

Use ceph orch host ls to view the hosts in your storage cluster:

Example

[root@host01 ~]# ceph orch host ls
HOST   ADDR   LABELS  STATUS
host01        mon,mgr,_admin
host02        mon
host03        mon,mgr
host04
host05
host06

Use the _admin label to designate the admin host in your storage cluster. For best results, this host should have both Monitor and Manager daemons running.

Syntax
```
ceph orch host label add HOSTNAME _admin
```
Example
```
[root@host01 ~]#  ceph orch host label add host03 _admin
```

Verify that the admin host has the _admin label.

Example

[root@host01 ~]#  ceph orch host ls
HOST   ADDR   LABELS  STATUS
host01        mon,mgr,_admin
host02        mon
host03        mon,mgr,_admin
host04
host05
host06