Summary

In certain situations, empty error messages can be seen in the status of a MachinePool

Steps to Reproduce

Deploy a cluster to AWS. For the MachinePool, specify 3 AZs similar to the following:

apiVersion: hive.openshift.io/v1
kind: MachinePool
metadata:
  name: kevin-3-zone-worker
  namespace: kevin-3-zone
spec:
  clusterDeploymentRef:
    name: kevin-3-zone
  name: worker
  platform:
    aws:
      rootVolume:
        iops: 2000
        size: 100
        type: io1
      type: m5.xlarge
      zones:
      - us-east-1a
      - us-east-1b
      - us-east-1c
  replicas: 3

After the cluster has deployed, enable auto-scaling on the MachinePool with maxReplicas less than the number of MachineSets by adding the following spec and removing the replicas count:

spec:
  autoscaling:
    maxReplicas: 2
    minReplicas: 1

Wait for a node to be removed, then remove the autoscaling stanza from the spec and restore replicas to 3. Immediately observe the status of the MachinePool.

Expected Results

Status should show valid status information for each of the machine sets.

Actual Results

Status of the MachinePool resembles the following, with empty string values for errorMessage and errorReason:

status:
...
  machineSets:
  - maxReplicas: 1
    minReplicas: 1
    name: kevin-3-zone-m5pfj-worker-us-east-1a
    readyReplicas: 1
    replicas: 1
  - maxReplicas: 1
    minReplicas: 1
    name: kevin-3-zone-m5pfj-worker-us-east-1b
    readyReplicas: 1
    replicas: 1
  - errorMessage: ""
    errorReason: ""
    maxReplicas: 1
    minReplicas: 1
    name: kevin-3-zone-m5pfj-worker-us-east-1c
    replicas: 1
  replicas: 3

Additional Information

The reproduction steps are the same as for https://issues.redhat.com/browse/HIVE-2415 with one additional step of disabling autoscaling. See Slack discussions in #forum-hive and #forum-ocm-cloud