carvel-dev / kapp

Service has its selector modified by kapp:

apiVersion: v1
kind: Service
spec:
  selector:
    app.kubernetes.io/component: prometheus
    app.kubernetes.io/instance: k8s
    app.kubernetes.io/name: prometheus
    app.kubernetes.io/part-of: kube-prometheus
    kapp.k14s.io/app: "1684079013099136212"

Leading to the Service not having any matching Pods.

Whereas StatefulSet does not have its spec.template.metadata.labels modified:

spec:
  template:
    metadata:
      labels:
        app.kubernetes.io/component: prometheus
        app.kubernetes.io/instance: k8s
        app.kubernetes.io/managed-by: prometheus-operator
        app.kubernetes.io/name: prometheus
        app.kubernetes.io/part-of: kube-prometheus
        app.kubernetes.io/version: 2.43.0
        operator.prometheus.io/name: k8s
        operator.prometheus.io/shard: "0"
        prometheus: k8s

Why is the selector modified at all?

What steps did you take:

Define a Service
Define a StatefulSet
Define selectors in Service to match the Labels in the StatefulSet Pod Template.
Deploy these two via kapp.

What happened:

kapp adds label to the Service
kapp adds label to the Service selector
kapp adds label to the StatefulSet.
kapp does NOT add labels to the StatefulSet Pod Template.

What did you expect:

One of:

label to not be added in Service selector
label to be added in Pod Template

Anything else you would like to add:

I would expect kapp to "just work" for passing something this simple throuigh it.

Environment:

kapp version (use kapp --version): kapp version 0.54.3
OS (e.g. from /etc/os-release): Ubuntu 22.04.1 LTS
Kubernetes version (use kubectl version) v1.22.17

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Hi @frimik!
kapp has some default labelScopingRules and ownershipRules to inject it's labels into resources. By default, kapp should inject the labels into the spec.template.metadata.labels of a statefulset (

kapp/pkg/kapp/config/default.go

Line 272 in 3e2edfa

- apiVersionKindMatcher: {apiVersion: apps/v1, kind: StatefulSet}

), unless you have the kapp.k14s.io/disable-default-ownership-label-rules annotation present (if this is not the case, could you share your StatefulSet yaml?). I tried creating a StatefulSet and I could see the labels under spec.template.metadata.labels.

kapp injects label in Service Selector but not StatefulSet Pod Template