Argo CD "config management plugin ... not found" in CI

When an Application uses a config management plugin (CMP), the repo-server must have that plugin registered as a sidecar. If the named plugin is not present, generation fails with a "plugin not found" error.

What this error means

The Application shows a ComparisonError with "config management plugin <name> not found" (or "plugin not supported"), and no manifests are produced.

argocd

rpc error: code = Unknown desc = Manifest generation error (cached):
config management plugin with name 'my-cmp' is not supported

Common causes

The plugin sidecar is not deployed

The Application references a CMP that has no matching sidecar container on the repo-server, so Argo CD cannot invoke it.

A name mismatch between app and plugin

The plugin name in the Application does not match the registered plugin manifest name, so lookup fails.

How to fix it

Register the plugin as a repo-server sidecar

Confirm the CMP sidecar is deployed on the repo-server.
Match the plugin name in the Application to the ConfigManagementPlugin name.
Hard-refresh so the app re-attempts generation with the plugin.

application.yaml

spec:
  source:
    plugin:
      name: my-cmp

Verify the plugin registration

Check that the plugin sidecar is present and its name matches what the Application requests.

Terminal

kubectl -n argocd get deploy argocd-repo-server -o yaml | grep -A2 name:

How to prevent it

Keep CMP sidecar names in sync with Application plugin names.
Deploy the plugin sidecar before pointing apps at it.
Prefer built-in tools (Helm/kustomize) unless a plugin is truly required.