In an environment where you have deployed a large Ceph cluster, you might want to increase your monitor count. Like in an OSD, adding new monitors to the Ceph cluster is an online process. In this recipe, we will configure ceph-node4 as a monitor node.

Since this is a test Ceph cluster, we will add ceph-node4 as the fourth monitor node. However, in the production setup, you should always have an odd number of monitor nodes in your Ceph cluster in order to form a quorum:

1. Update the /etc/ansible/hosts file with ceph-node4 under the [mons] section:
   
2. Run the Ansible playbook to deploy the new MON on ceph-node4:

root@ceph-node1 ceph-ansible # ansible-playbook site.yml

3. Once ceph-node4 is configured as a monitor node, check the ceph status to see the cluster status. Please note that ceph-node4 is your new monitor node:

4. Check the Ceph monitor status and notice ceph-node4 as the new Ceph monitor: