Chapter 6. Downgrading OpenShift

Following an OpenShift Container Platform upgrade, it may be desirable in extreme cases to downgrade your cluster to a previous version. The following sections outline the required steps for each system in a cluster to perform such a downgrade for the OpenShift Container Platform 3.5 to 3.4 downgrade path.

The Ansible playbook used during the upgrade process should have created a backup of the master-config.yaml file and the etcd data directory. Ensure these exist on your masters and etcd members:

/etc/origin/master/master-config.yaml.<timestamp>
/var/lib/origin/etcd-backup-<timestamp>

Also, back up the node-config.yaml file on each node (including masters, which have the node component on them) with a timestamp:

/etc/origin/node/node-config.yaml.<timestamp>

If you use a separate etcd cluster instead of a single embedded etcd instance, the backup is likely created on all etcd members, though only one is required for the recovery process. You can run a separate etcd instance that is co-located with your master nodes.

The RPM downgrade process in a later step should create .rpmsave backups of the following files, but it may be a good idea to keep a separate copy regardless:

/etc/sysconfig/atomic-openshift-master
/etc/etcd/etcd.conf 

On all masters, nodes, and etcd members, if you use a separate etcd cluster that runs on different nodes, ensure the relevant services are stopped.

On the master in a single master cluster:

# systemctl stop atomic-openshift-master

On each master in a multi-master cluster:

# systemctl stop atomic-openshift-master-api
# systemctl stop atomic-openshift-master-controllers

On all master and node hosts:

# systemctl stop atomic-openshift-node

On any etcd hosts for a separate etcd cluster:

# systemctl stop etcd

Both OpenShift Container Platform 3.4 and 3.5 require Docker 1.12, so Docker does not need to be downgraded.

Disable the OpenShift Container Platform 3.5 repositories, and re-enable the 3.4 repositories:

# subscription-manager repos \
    --disable=rhel-7-server-ose-3.5-rpms \
    --enable=rhel-7-server-ose-3.4-rpms

On each master, install the following packages:

# yum install atomic-openshift \
    atomic-openshift-clients \
    atomic-openshift-node \
    atomic-openshift-master \
    openvswitch \
    atomic-openshift-sdn-ovs \
    tuned-profiles-atomic-openshift-node \
    atomic-openshift-excluder \
    atomic-openshift-docker-excluder

On each node, install the following packages:

# yum install atomic-openshift \
    atomic-openshift-node \
    openvswitch \
    atomic-openshift-sdn-ovs \
    tuned-profiles-atomic-openshift-node \
    atomic-openshift-excluder \
    atomic-openshift-docker-excluder

If you use a separate etcd cluster, install the following package on each etcd member:

# yum install etcd

See Backup and Restore.

See Backup and Restore.