Server-Side Apply field conflict with "cluster-proportional-autoscaler" with subresource "scale" using apps/v1: .spec.replicas

[mattburgess]

What happened?

We deploy metrics-server using a Helm chart and have a cluster-proportional-autoscaler deployment alongside it to manage its scale. If CPA has scaled the metrics-server deployment we see this error when trying to run a pulumi up or pulumi preview:

error: Preview failed: 1 error occurred:
	* the Kubernetes API server reported that "kube-system/metrics-server" failed to fully initialize or become live: Server-Side Apply field conflict detected. See https://www.pulumi.com/registry/packages/kubernetes/how-to-guides/managing-resources-with-server-side-apply/#handle-field-conflicts-on-existing-resources for troubleshooting help
: Apply failed with 1 conflict: conflict with "cluster-proportional-autoscaler" with subresource "scale" using apps/v1: .spec.replicas

Example

This is our helm chart code, including the suggestion from the above ticket:

    const deployment = new k8s.helm.v3.Chart(
      "metrics-server",
      {
        namespace: "kube-system",
        path: helmPath(`metrics-server/v${args.chartVersion}`),
        values: {
          // https://github.com/kubernetes-sigs/metrics-server#scaling
          image: {
            repository: `${args.ECRMk8sBase}/release/k8s.gcr.io/metrics-server/metrics-server`,
          },
          resources: {
            requests: {
              memory: "200Mi",
              cpu: "100m",
            },
            limits: {
              memory: "1Gi",
            },
          },
          podDisruptionBudget: {
            enabled: true,
            minAvailable: 1,
          },
          replicas: minimumReplicas,
        },
        transformations: [
          // eslint-disable-next-line @typescript-eslint/no-explicit-any,@typescript-eslint/no-shadow
          (obj: any, opts: pulumi.CustomResourceOptions) => {
            if (obj.kind === "Deployment" && obj.metadata.name === "metrics-server") {
              // eslint-disable-next-line no-param-reassign
              opts.ignoreChanges = ["spec.replicas"];
            }
          },
        ],
      },
      {
        parent: this,
      }
    );

Output of pulumi about

CLI
Version      3.133.0
Go Version   go1.23.1
Go Compiler  gc

Plugins
KIND      NAME        VERSION
resource  aws         6.56.1
resource  kubernetes  4.5.3
language  nodejs      unknown
resource  random      4.16.7

Host
OS       darwin
Version  14.7.1
Arch     arm64

Additional context

No response

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[blampe]

@mattburgess I suggest adding some debug logging to confirm whether your transformation is actually getting applied. I suspect it might not be.

Do you see the same problem when using v4.Chart with a transform (not transformation)?