Bug 2042366

Description of problem:

Currently, the lifecycle hook maps are considered atomic, if a controller is managing their own lifecycle hook, they may accidentally overwrite another controllers hook.

Server side apply account for this by allowing to specify the list as a map.

Version-Release number of selected component (if applicable):


How reproducible: 100%


Steps to Reproduce:
1. Create two machine yamls for the same machine with different hooks, eg:
apiVersion: machine.openshift.io/v1beta1

kind: Machine
metadata:
  name: list-map-machine
spec:
  lifecycleHooks:
    preDrain:
    - name: hook1
      owner: hookOwner1

apiVersion: machine.openshift.io/v1beta1
kind: Machine
metadata:
  name: list-map-machine
spec:
  lifecycleHooks:
    preDrain:
    - name: hook2
      owner: hookOwner2

2. Apply the file first with one client: kubectl apply --server-side --field-manager client1 -f machine-hook1.yaml
3. Then the second using a second client: kubectl apply --server-side --field-manager client2 -f machine-hook2.yaml

Actual results:
An error occurs because the list is atomic, you need to force apply the second file which overwrites the first hook

Expected results:
Both hooks should be accepted and be listed with separate field managers

apiVersion: machine.openshift.io/v1beta1
kind: Machine
metadata:
  creationTimestamp: "2022-01-19T10:48:47Z"
  generation: 2
  managedFields:
  - apiVersion: machine.openshift.io/v1beta1
    fieldsType: FieldsV1
    fieldsV1:
      f:spec:
        f:lifecycleHooks:
          f:preDrain:
            k:{"name":"hook1"}:
              .: {}
              f:name: {}
              f:owner: {}
    manager: client1
    operation: Apply
    time: "2022-01-19T10:48:47Z"
  - apiVersion: machine.openshift.io/v1beta1
    fieldsType: FieldsV1
    fieldsV1:
      f:spec:
        f:lifecycleHooks:
          f:preDrain:
            k:{"name":"hook2"}:
              .: {}
              f:name: {}
              f:owner: {}
    manager: client2
    operation: Apply
    time: "2022-01-19T10:49:05Z"
  name: list-map-machine
  namespace: default
  resourceVersion: "2297"
  uid: ba6012e1-10b8-426f-8ed0-9495282fb3eb
spec:
  lifecycleHooks:
    preDrain:
    - name: hook1
      owner: hookOwner1
    - name: hook2
      owner: hookOwner2

Additional info: