Migrating automatically-provisioned services

MicroCeph deploys automatically-provisioned Ceph services when needed. These services include:

• MON - Monitor service

• MDS - Metadata service

• MGR - Manager service

It can however be useful to have the ability to move (or migrate) these services from one node to another. This may be desirable during a maintenance window for instance where these services must remain available.

This is the purpose of the cluster migrate command. It enables automatically-provisioned services on a target node and disables them on the source node.

The syntax is:

sudo microceph cluster migrate <source> <destination>

Where the source and destination are node names that are available via the status command:

sudo microceph status

Post-migration, the status command can also be used to verify the distribution of services among nodes.

Notes:

• It’s not possible, nor useful, to have more than one instance of an automatically-provisioned service on any given node.

• RADOS Gateway services are not considered to be of the automatically-provisioned type; they are enabled and disabled explicitly on a node.