Chapter 5. Updating Operating Systems

Ensure the host is unschedulable, meaning that no new pods will be placed onto the host:

$ oc adm manage-node <node_name> --schedulable=false

Migrate the pods from the host:

$ oc adm drain <node_name> --force --delete-local-data --ignore-daemonsets

In order to protect sensitive packages that do not need to be updated, apply the exclude rules to the host:

# atomic-openshift-docker-excluder exclude
# atomic-openshift-excluder exclude

Update the host packages and reboot the host. A reboot ensures that the host is running the newest versions and means that the docker and OpenShift Container Platform processes have been restarted, which forces them to check that all of the rules in other services are correct.

 # yum update
 # reboot

However, instead of rebooting a node host, you can restart the services that are affected or preserve the iptables state. Both processes are described in the OpenShift Container Platform iptables topic. The ovs flow rules do not need to be saved, but restarting the OpenShift Container Platform node software fixes the flow rules.

Configure the host to be schedulable again:

$ oc adm manage-node <node_name> --schedulable=true