etcd cluster lifecycle in etcd operator

Let's talk about the lifecycle of etcd cluster "A".

  • Initially, "A" doesn't exist. Operator considers this cluster has 0 members. Any cluster with 0 members would be considered as non-existed.
  • At some point of time, a user creates an object for "A". Operator would receive "ADDED" event and create this cluster. For the entire lifecycle, an etcd cluster could be created only once.
  • Then user might update 0 or more times on the spec of "A". Operator would receive "MODIFIED" events and reconcile actual state gradually to desired state of given spec.
  • Finally, a user deletes the object of "A". Operator will delete and recycle all resources of "A". For the entire lifecycle, an etcd cluster could be deleted only once.