Centos Container Pipeline OpenShift Upgrade Part 3 - 'Ready for Production!'

This blog is a part of the series of blogs on OpenShift OKD upgrade we performed for the CentOS Container Pipeline project. If you haven’t read the first part and the second part, this post might not make a lot of sense. Go ahead, read them first.

I ended the previous post with describing the unconventional path we unwillingly decided to go with and how that led us to figure the cause of the issue we were facing while following recommended path for OKD 3.9 to 3.10 upgrade.

Uninstall, install, repeat

As mentioned in the previous post, the idea was to:

Just like OKD 3.10, OKD 3.11 also uses openshift_node_groups dictionary in place of openshift_node_labels and takes the configuration for kubelet arguments with it.

While installing OKD 3.11, we encountered an issue wherein Ansible playbook would exit with an error related to OpenShift master. The error was:

{"changed": false, "msg": "Node start failed."}

This kept on repeating every time we tried to install OKD 3.11 on the nodes where OKD 3.9 was earlier installed.

Fixed two issues in one shot

We opened an issue on GitHub for the installation error. Unlike the failure with OKD 3.10 upgrade, this time the logs were more helpful in making sense of the underlying issue.

It seemed like we made a mistake in configuring the value for openshift_node_groups variable. My takeaway from the way we fixed the issue is that the value in the dictionary has to be a list even if it’s just one value and not multiple values.

After this we faced another error that had to do with the value we had set for the key kubeletArguments.image-gc-high-threshold in openshift_node_groups. This is something I found from the logs. After trying few values that I thought might help origin-node service to start well, I gave up and removed every configuration related to garbage collector from the openshift_node_groups variable.

This not only helped us perform a successful installation of OKD 3.11, but also turned on a bulb in my head that illuminated something like, “Remove the garbage collector configuration and try OKD 3.9 to OKD 3.10 upgrade the recommended way!” And so I did.

Successful OKD 3.9 to OKD 3.10 upgrade

It turned out that the bulb illuminated the right thing. Apart from facing a few minor issues (minor because we didn’t need to open a GitHub issue), we managed to upgrade our OKD 3.9 cluster OKD 3.10 using the OpenShift Ansible playbooks! It was a “F**k yeah” moment for me.

Over next few days, we managed to successfully perform OKD 3.9 to OKD 3.10 upgrade in the development environment before we decided to replicate the steps in production.

That’s it!

Since the recommended upgrade path worked well for us, we didn’t bother to test if doing uninstall and install of different versions of OKD and then using the same PV for a persistent Jenkins deployment worked well or not. We felt ecstatic with the way things worked out. Little did we know how the Jenkins thing was going to be one among several dogs that were planning on biting us!

By the time we reached this point, it was more than 3 weeks since we started off. I visited the Serengeti National Park during this timeframe and if we count the vacation, it was more than 4 weeks since we started.

Until next time… 😄

w