Module 4 - Scaling up a Ceph cluster¶
## Note: ## Before proceeding with this module make sure you have completed Module-1 and have a running Ceph cluster.
Ceph is designed to scale to exabyte level. Scaling a Ceph cluster is a matter of just adding nodes and Ceph will take care of the rest. In this module we will add a new OSD node osd-node4
with 3 drives to our existing Ceph cluster of 3 OSD nodes.
- We currently have 3 OSD Ceph cluster with total 9 OSDs, lets verify it again
$ ceph osd stat $ ceph osd tree
Once new node osd-node4
is added we will then have 4 Node Ceph cluster with 12 disks altogether.
-
To scale up Ceph cluster, login to
mgmt
node which is our ceph-ansible node -
Edit
/etc/ansible/hosts
file
$ sudo vi /etc/ansible/hosts
- Add
osd-node4
under[osds]
section. Save and exit editor
[mons] mon-node1 mon-node2 mon-node3 [osds] osd-node1 osd-node2 osd-node3 osd-node4 [rgws] rgw-node1
- Navigate to the Ansible configuration directory
/usr/share/ceph-ansible/
$ cd /usr/share/ceph-ansible/
- Now run Ansible playbook, which will make sure
osd-node4
is added to existing Ceph cluster
$ ansible-playbook site.yml -u ceph
- Once Ansible run is completed, make sure there is no failed item under
PLAY RECAP
- So ceph-ansible has scaled up our Ceph cluster, lets verify it
$ ceph osd stat $ ceph osd tree $ ceph -s
At this point we have scaled up our Ceph cluster to 4 OSD node, without any downtime or service breaks. This shows, how seamless is Ceph scale up operation