Impacts

When updating or upgrading your operating system (OS), either changing OS versions or updating the system software, be aware that this can impact the OpenShift Container Platform software running on those machines. In particular, these updates can affect the iptables rules or ovs flows that OpenShift Container Platform requires to operate.

Solutions

Reboot the node to ensure that all of the software is running the new versions, especially if a new kernel is installed. A reboot will also ensure that the docker and OpenShift Container Platform processes have been restarted, which will force them to check that all of the rules in other services are correct.

However, if you do not wish to do a reboot of the node, then it is possible to just restart the services that are affected, or to 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 will fix the flow rules.