Issues with Argo Rollout Controller and Custom Sidecar Injection

[mlajkim]

Hello,

I have a few questions regarding the Argo Rollout controller.

We had a customized controller in place before installing the Argo Rollout controller. This customized controller attaches a sidecar to any pods created in the cluster using a Kubernetes webhook. It injects a container for any YAML provided by users that includes a special label called inject-sidecar=true. This setup has been working perfectly so far.

Recently, we decided to implement Argo Rollouts, so we installed the Argo Rollout controllers and the CRD for Rollouts. We tested it with a sample YAML, and it worked fine, updating as expected.

However, we later decided that the customized controller should inject an environment variable (DISABLE_FEATURE=true) for our team-managed sidecar (but not for other sidecars). After making this change, the Argo Rollout controllers started failing. The error message indicates that the Argo Rollout is trying to modify a running pod's field, which is not allowed in Kubernetes.

I am wondering if others have faced similar issues when two operators work together. Any insights or suggestions would be greatly appreciated.

Thank you!

[mlajkim]

This happened due to poor implementation of our mutation webhook.