versioned-explicit-ref does not work for all resource types

[rdicroce]

What steps did you take:

1. Deploy the below.
2. Change test: x to test: x2.
3. Deploy again.

---
apiVersion: batch/v1
kind: Job
metadata:
  name: foo-job
  annotations:
    kapp.k14s.io/update-strategy: always-replace
    kapp.k14s.io/change-group: job-group
    kapp.k14s.io/versioned: ""
    test: x
spec:
  template:
    spec:
      restartPolicy: Never
      containers:
        - name: busybox
          image: busybox:1.36.1
          command: 
            - /bin/sh
            - -ec
            - sleep 5
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: simple-app
  annotations:
    kapp.k14s.io/change-rule: upsert after upserting job-group
    kapp.k14s.io/versioned-explicit-ref: |
      apiVersion: batch/v1
      kind: Job
      name: foo-job
spec:
  selector:
    matchLabels:
      simple-app: ""
  template:
    metadata:
      labels:
        simple-app: ""
    spec:
      containers:
      - name: simple-app
        image: busybox:1.36.1
        command:
          - /bin/sh
          - -ec
          - while :; do echo '.'; sleep 5 ; done

What happened: The Job was updated, but the Deployment was not.

What did you expect: The Deployment should have been updated after the Job, because of the change-rule and the versioned-explicit-ref.

Anything else you would like to add: From looking at the kapp docs, it seems like the Deployment's versioned-explicit-ref annotation is supposed to contain the versioned name when it's written to Kubernetes. But it doesn't - the Kubernetes dashboard shows the annotation still has the unversioned name.

Environment:

• kapp version (use kapp --version): 0.63.1
• OS (e.g. from /etc/os-release): Windows 10
• Kubernetes version (use kubectl version): 1.30.0

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[100mik]

I think what happening here is a weird interaction between the annotation kapp.k14s.io/update-strategy: always-replace and the explicit-version-ref. Mainly cause versioning happens on update and according to the strategy the job is always created again. I will reproduce this locally and take a peek at what happens.

What is your reason for using the update strategy?

[rdicroce]

I'm new to K8s and kapp, and I discovered quickly that K8s won't allow some fields to be modified by an update. Hence, the Job has to be deleted and recreated.

[100mik]

I discovered quickly that K8s won't allow some fields to be modified by an update. Yep, this would be true for spec.Template and I believe you will be trying to bump the images here.

This would be a valid use case, I am curious about if it is indeed the cause. To have a path forward today, we could rely on a fixed tag, and use the default update strategy, however, I am not saying that we should not improve this behaviour.

[rdicroce]

Right now, I'm working around the problem by:

1. Putting an annotation on both objects.
2. Creating a "constants" file that contains a value for the annotation.
3. Referencing that constant as the value for both annotations.

Then, if either object needs to be updated, I change the constant. It's basically a manual way of doing what explicit-version-ref is supposed to do. It works, but it's clunky.

[rdicroce]

After some more experimentation, I've determined that the update-strategy does not matter. If you remove it in the original example I posted above, the explicit-version-ref still doesn't work. And if you replace the Job with a ConfigMap that uses the always-replace strategy (see below), it works fine. And if you replace the Job with a Service, it half works: the Service has -ver-x appended to its name, but the explicit-version-ref annotation on the Deployment does not.

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: config-1
  annotations:
    kapp.k14s.io/versioned: ""
    kapp.k14s.io/update-strategy: always-replace
    kapp.k14s.io/change-group: job-group
    test: x
data:
  foo: bar
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: simple-app
  annotations:
    kapp.k14s.io/change-rule: upsert after upserting job-group
    kapp.k14s.io/versioned-explicit-ref: |
      apiVersion: v1
      kind: ConfigMap
      name: config-1
spec:
  selector:
    matchLabels:
      simple-app: ""
  template:
    metadata:
      labels:
        simple-app: ""
    spec:
      containers:
      - name: simple-app
        image: busybox:1.36.1
        command:
          - /bin/sh
          - -ec
          - while :; do echo '.'; sleep 5 ; done