Ceph: Designing and Implementing Scalable Storage Systems

Adding the Ceph MON

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 ...