Manually deploying a mgr daemon

Edit online

Cephadm requires a mgr daemon in order to manage the IBM Storage Ceph cluster. In case the last mgr daemon of an IBM Storage Ceph cluster was removed, you can manually deploy a mgr daemon, on a random host of the IBM Storage Ceph cluster.

Prerequisites

Edit online

  • A running IBM Storage Ceph cluster.

  • Root-level access to all the nodes.

  • Hosts are added to the cluster.

Procedure

Edit online

  1. Log into the Cephadm shell:

    Example 

    [root@host01 ~]# cephadm shell

  2. Disable the Cephadm scheduler to prevent Cephadm from removing the new MGR daemon, with the following command:

    Example 

    [ceph: root@host01 /]# ceph config-key set mgr/cephadm/pause true

  3. Get or create the auth entry for the new MGR daemon:

    Example 

    [ceph: root@host01 /]# ceph auth get-or-create mgr.host01.smfvfd1 mon "profile mgr" osd "allow *" mds "allow *"
[mgr.host01.smfvfd1]
key = AQDhcORgW8toCRAAlMzlqWXnh3cGRjqYEa9ikw==

  4. Open ceph.conf file:

    Example 

    [ceph: root@host01 /]# ceph config generate-minimal-conf
# minimal ceph.conf for 8c9b0072-67ca-11eb-af06-001a4a0002a0
[global]
fsid = 8c9b0072-67ca-11eb-af06-001a4a0002a0
mon_host = [v2:10.10.200.10:3300/0,v1:10.10.200.10:6789/0] [v2:10.10.10.100:3300/0,v1:10.10.200.100:6789/0]

  5. Get the container image:

    Example 

    [ceph: root@host01 /]# ceph config get "mgr.host01.smfvfd1" container_image
  6. Create a config-json.json file and add the following:
    Note: Use the values from the output of the ceph config generate-minimal-conf command.

    Example 

    {
  {
  "config": "# minimal ceph.conf for 8c9b0072-67ca-11eb-af06-001a4a0002a0\n[global]\n\tfsid = 8c9b0072-67ca-11eb-af06-001a4a0002a0\n\tmon_host =  [v2:10.10.200.10:3300/0,v1:10.10.200.10:6789/0] [v2:10.10.10.100:3300/0,v1:10.10.200.100:6789/0]\n",
  "keyring": "[mgr.Ceph5-2.smfvfd1]\n\tkey = AQDhcORgW8toCRAAlMzlqWXnh3cGRjqYEa9ikw==\n"
}
}

  7. Exit from the Cephadm shell:

    Example 

    [ceph: root@host01 /]# exit

  8. Deploy the MGR daemon:

    Example 

    [root@host01 ~]# cephadm --image cp.icr.io/cp/ibm-ceph/ceph-7-rhel9:latest deploy --fsid  8c9b0072-67ca-11eb-af06-001a4a0002a0 --name mgr.host01.smfvfd1 --config-json config-json.json

Verification

Edit online

  • In the Cephadm shell, run the following command:

    Example 

    [ceph: root@host01 /]# ceph -s

    You can see a new mgr daemon has been added.