Recently, I had to explore the new features in the new release candidate version of OpenShift. Unfortunately, I did not have access to such a cluster. So I had to use an older stable version and upgrade it. The process is simple enough, and even easily scriptable. Here is how.
Find Your Upgrade Path
I’ve had a few issues upgrading from version 4.3.5 directly to 4.4.0-rc.8. When I tried to upgrade to 4.3.9 first, I had much more success. So it seems like a direct upgrade might now possible. In my case, the path was 4.3.5->4.3.9->4.4.0-rc.8 which worked successfully on a few attemps now.
Update The Available Cluster Versions
You can see the list of available upgrades to you by using
oc adm upgrade
You can update this list by patching the clusterversions. To do so, tell OpenShift to query a channel to find available versions. TYou will need to specify either stable, fast or candidate and a specific version number. To find the 4.3.x stable upgrades
oc patch clusterversions/version -p '{"spec":{"channel":"stable-4.3"}}' --type=merge
To find the release candidates for 4.4
oc patch clusterversions/version -p '{"spec":{"channel":"candidate-4.4"}}' --type=merge
This process will take a few seconds. You should see the version you want to upgrade to in the list provided by oc adm upgrade.
Upgrade the cluster
You are now ready to upgrade OpenShift. You can use the following command to do so.
oc adm upgrade --to=<OPENSHIFT_VERSION>
The process will take anywhere between 30 and 90 minutes. You can see the progress with
oc get clusterversion
Eventually, you will see that the upgrade was completed successfully.
That's it, that's all you need to upgrade OpenShift from the CLI. To simplify all this, I wrote a small script.
echo "Time to upgrade!"
echo "What version do you want to upgrade to?"
read OPENSHIFT_UPGRADE_VERSION
echo "Upgrading this cluster to version $OPENSHIFT_UPGRADE_VERSION"
# You might need to change the channel here
oc patch clusterversions/version -p '{"spec":{"channel":"candidate-4.4"}}' --type=merge
echo "Waiting 2 minutes for patching to happen..."
sleep 150
echo "Ready to upgrade cluster to version $OPENSHIFT_UPGRADE_VERSION"
echo "This will take approximately 30-60 minutes"
echo "You should get an update every minute or so"
oc adm upgrade --to $OPENSHIFT_UPGRADE_VERSION
sleep 120
while [ $(oc get clusterversion | awk '{print $4}' | grep True) ]; do
echo $(oc get clusterversion | awk 'FNR == 2 { s = ""; for (i = 6; i <= NF; i++) s = s $i " "; print s }')
sleep 120
done
echo "Cluster should have been upgraded now, you can verify here"
oc get clusterversion
All Done!
That's it! You can now upgrade OpenShift to the latest version to explore the new features that are available to you.