configmap and content aware hashing

[tcurdt]

I really don't get the config map hashing feature as documented.

What I want:

List all the configmaps in the config that should be renamed to their name with their content hash added as a suffix.

Is this possible or not? The configMapGenerator does not really seem to help here.

What I tried

resources:
- infra/caddy.yaml

configMapGenerator:
  - name: caddy
    files:
      - infra/caddy.yaml

Which already is a bit flawed because I want configmap caddy - but in the infra namespace.
What I would like is to have this modification:

apiVersion: v1
kind: ConfigMap
metadata:
  namespace: infra
  name: caddy-HASH
  labels:
    app: caddy
data:
  Caddyfile: |
    ...

...
      volumes:
        - name: caddy-config
          configMap:
            name: caddy-HASH

[ChristianCiach]

You cannot use Kustomize to add a hash-suffix to an existing ConfigMap that you are providing yourself. Kustomize only adds hash-suffixes to ConfigMaps that are generated by Kustomize.

I assume the file infra/caddy.yaml from your example is actually a ConfigMap containing the Caddy configuration, right?

What you should do is this:

resources:
  - deployment.yaml # or some other workload that consumes the ConfigMap named `caddy-config`

configMapGenerator:
  - name: caddy-config
    files:
      - Caddyfile

[tcurdt]

You cannot use Kustomize to add a hash-suffix to an existing ConfigMap that you are providing yourself. Kustomize only adds hash-suffixes to ConfigMaps that are generated by Kustomize.

You can. It is just not documented and uses an internal annotation - but it works.
And it would be nice to turn it into an officially supported feature.

TLDR: This annotation does the trick to apply hashes to existing configmaps.

internal.config.kubernetes.io/needsHashSuffix: enabled

Unfortunately the problem is also is a bit more complex than it should be.
Is a merged map a generated one or not?

If I merge a generated map with an existing map the hash does not get applied either.
I really wish this would follow the KISS principle.

#5712

What you should do is this:

That's really not what I want to do though.