This tutorial will show how to install MicroCeph on a single machine, thereby creating a single-node “cluster”.
Ensure storage requirements¶
Three OSDs will be required to form a minimal Ceph cluster. This means that three entire disks are required to be available on the machine.
Upstream Ceph development is underway to allow for loopback device support. This will filter down to MicroCeph which will allow for easier proof-of-concept and developer deployments.
The disk subsystem can be inspected with the lsblk command. In this tutorial, the command’s output is shown below. Any output related to possible loopback devices has been suppressed for the purpose of clarity:
lsblk | grep -v loop NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS sda 8:0 0 931.5G 0 disk sdb 8:16 0 931.5G 0 disk sdc 8:32 0 931.5G 0 disk sdd 8:48 0 931.5G 0 disk nvme0n1 259:0 0 372.6G 0 disk ├─nvme0n1p1 259:1 0 512M 0 part /boot/efi └─nvme0n1p2 259:2 0 372.1G 0 part /
There are four disks available, here we will use disks
Install the software¶
Install the most recent stable release of MicroCeph:
sudo snap install microceph
Next, prevent the software from being auto-updated:
sudo snap refresh --hold microceph
Allowing the snap to be auto-updated can lead to unintended consequences. In enterprise environments especially, it is better to research the ramifications of software changes before those changes are implemented.
Initialise the cluster¶
Begin by initialising the cluster with the cluster bootstrap command:
sudo microceph cluster bootstrap
Then look at the status of the cluster with the status command:
sudo microceph status
It should look similar to the following:
MicroCeph deployment summary: - node-mees (10.246.114.49) Services: mds, mgr, mon Disks: 0
Here, the machine’s hostname of ‘node-mees’ is given along with its IP address of ‘10.246.114.49’. The MDS, MGR, and MON services are running but there is not yet any storage available.
Add the three disks to the cluster by using the disk add command:
sudo microceph disk add /dev/sda --wipe sudo microceph disk add /dev/sdb --wipe sudo microceph disk add /dev/sdc --wipe
Adjust the above commands according to the storage disks at your disposal.
sudo microceph status
The output should now show three disks and the additional presence of the OSD service:
MicroCeph deployment summary: - node-mees (10.246.114.49) Services: mds, mgr, mon, osd Disks: 3
Manage the cluster¶
Your Ceph cluster is now deployed and can be managed by following the resources found in the Howto section.
The cluster can also be managed using native Ceph tooling if snap-level commands are not yet available for a desired task:
The cluster built during this tutorial gives the following output:
cluster: id: 4c2190cd-9a31-4949-a3e6-8d8f60408278 health: HEALTH_OK services: mon: 1 daemons, quorum node-mees (age 7d) mgr: node-mees(active, since 7d) osd: 3 osds: 3 up (since 7d), 3 in (since 7d) data: pools: 1 pools, 1 pgs objects: 2 objects, 577 KiB usage: 96 MiB used, 2.7 TiB / 2.7 TiB avail pgs: 1 active+clean