Microceph upgrade

https://canonical-microceph.readthedocs-hosted.com/en/latest/how-to/reef-upgrade/

https://canonical-microceph.readthedocs-hosted.com/en/latest/_sources/how-to/major-upgrade.rst.txt

Overview
This guide provides step-by-step instructions on how to upgrade your MicroCeph cluster from the Quincy release to the Reef release. Follow these steps carefully to prevent to ensure a smooth transition.

Procedure
Optional but Recommended: Preparation Steps
Carry out these precautionary steps before initiating the upgrade:

Back up your data: as a general precaution, it is recommended to take a backup of your data (such as stored S3 objects, RBD volumes, or cephfs filesystems).

Prevent OSDs from dropping out of the cluster: Run the following command to avoid OSDs from unintentionally dropping out of the cluster during the upgrade process:

sudo ceph osd set noout
Checking Ceph Health
Before initiating the upgrade, ensure that the cluster is healthy. Use the below command to check the cluster health:

sudo ceph -s
Note: Do not start the upgrade if the cluster is unhealthy.

Upgrading Each Cluster Node
If your cluster is healthy, proceed with the upgrade by refreshing the snap on each node using the following command:

sudo snap refresh microceph --channel reef/stable
Be sure to perform the refresh on every node in the cluster.

Verifying the Upgrade
Once the upgrade process is done, verify that all components have been upgraded correctly. Use the following command to check:

sudo ceph versions
Unsetting Noout
If you had previously set noout, unset it with this command:

sudo ceph osd unset noout
Upgrade is complete.