Helm chart: be able to set update strategy

[JeroenVanOort]

Is your feature request related to a problem? Please describe.
Using the helm chart, I installed the nginx Ingress Controller on a 3 node cluster. Because I want the controller to run on every node, I set controller.replicaCount to 3. But when I update the helm deployment, it will try to start a 4th pod to replace one of the first 3. The update fails, because that new pod will try to bind to a specific port on the node, which already has an old pod bound to it.

Describe the solution you'd like
What I would like to do, is to set .spec.strategy.rollingUpdate.maxUnavailable to 1 and set .spec.strategy.rollingUpdate.maxSurge to 0. I believe this would make Kubernetes remove one of the old pods, create a new pod after that, and continue doing so until all pods have been replaced by new ones. But the total number of pods is never above the value of replicaCount.

In order to do this, I'd like to be able to specify .spec.strategy.rollingUpdate as a value in the Helm chart.

Describe alternatives you've considered
I've tried lowering the replicaCount, in order to allow a new container to be started and then setting the replicaCount back to 3 again. It works, but feels more like a hack than a solid solution.

Additional context
I'm willing to put time in creating a PR, but I would like to know how you think about this first.

Aha! Link: https://nginx.aha.io/features/IC-99

[github-actions]

Hi @JeroenVanOort thanks for reporting!

Be sure to check out the docs while you wait for a human to take a look at this 🙂

Cheers!

[pleshakov]

Hi @JeroenVanOort

I wonder if it makes sense to deploy Ingress Controller as a daemonset in your case, via controller.kind paramerer. Would it solve your issue?

[wd]

I am using daemonset now, but I also want to set the .spec.strategy.type to onDelete , so that I can control the pod terminate/create process manually.

[JeroenVanOort]

I wonder if it makes sense to deploy Ingress Controller as a daemonset in your case, via controller.kind paramerer. Would it solve your issue?

It does! Thank you very much. For me, this issue can be closed. However, others might still like to influence the strategy.

[pleshakov]

Thanks. We'll keep it issue open for the strategy related parameters.

[pdabelf5]

The ability to add the strategy to the helm chart was added in #2672