Storage Migration¶
From R5 release, StarlingX provides two storage solution, host-based ceph and rook-ceph. The second storage solution is containerized ceph solution. For an already deployed starlingx system with host-based ceph, after an upgrade to a starlingx release supporting rook-ceph, one could migrate from host-based ceph storage to rook-ceph storage to container-based ceph storage.
The migration procedure maintains CEPH OSDs and data on OSDs. Although the procedure does result in hosted applications experiencing several minutes of service outage due to temporary loss of access to PVCs or virtual disks, due to the temporary loss of the ceph service.
The step-by-step migration guides for the different configuration options are listed at the end of this page. The following provides an overall summary of the migration procedures.
Enable authentication for all ceph daemons
Rook-ceph must deploy with authentication, so before migration, config all ceph daemons with cephx.
Create secret and configmap for rook deployment
For migration, create configmap “rook-ceph-mon-endpoints” and secret “rook-ceph-mon” to save client.admin keyring and fsid.
Remove application platform-integ-apps
Disable HA for ceph daemon
Disable pmon and service manager’s monitoring for ceph daemons.
Create configmap to save OSD disk mount path
Because original ceph osd(s) are deployed with filestore, must create configmap to save osd disk info. Rook will look up configmap “rook-ceph-osd-<hostname>-config” to get every host’s osd info. In this configmap ‘osd-dirs: ‘{“<path>”:<osd-id>}’’ means, osd with this id, mount to this folder <path>/osd<id>.
Exit all ceph daemon
Assign label for rook-ceph
Assign label “ceph-mon-placement=enabled” and “ceph-mgr-placement=enabled” to controller-0.
Copy mon data to /var/lib/ceph/mon-a/data folder on controller-0
Rook-ceph will launch mon pod on host with label “ceph-mon-placement=enabled”. And the mon pod will use folder /var/lib/ceph/mon-<id>/data, so use ceph-monstore-tool copy mon-data to this folder. As rook launch mon with id a,b,c…, the first mon pod must use folder /var/lib/ceph/mon-a/data.
Edit monmap
Get monmap for /var/lib/ceph/mon-a/data, edit to update mon item with mon.a and controller-0 ip, and inject to mon-a data folder.
Apply application rook-ceph-apps
Rook-ceph will register CRD CephCluster and launch a containerized ceph cluster. By read above setting, this containerized ceph cluster will use original mon data and OSD data.
Launch more mon pods
After containerized ceph cluster launch, for duplex and multi, assign label to other 2 hosts, and change mon count to 3, with “kubectl edit CephCluster”.
Edit pv and pvc provisioner
For already created pv and pvc in openstack, if stx-openstack application is applied before migration, change the provisioner to kube-system.rbd.csi.ceph.com from rbd/ceph.com, as csi pod will provide csi service to K8s.
Update keyring and conf file on controller-0, controller-1
For k8s pv, it will use host /etc/ceph/keyring for ceph cluster access, update folder /etc/ceph/ with containerized ceph cluster.
Update helm override value for application stx-openstack
Update helm override value for cinder, to change provisoner from rbd/ceph.com to kube-system.rbd.csi.ceph.com.
Edit secret ceph-admin to update keyring
Update keyring in ceph-admin
Re-apply application stx-openstack
