Emit Kubernetes Events

[HarshwardhanPatil07]

Pool Events:

• ImageUpdateAvailable
• RolloutStarted
• RolloutCompleted
• Warning Events when the pool enters or changes a degraded state

Node Events:

• Staging
• Staged
• Rebooting
• DrainFailed
• DrainTakingTooLong

Node Events reference the BootcNode as the primary object and the owning BootcNodePool as the related object.

Testing

Completed: Manual Event verification on a bink cluster

make buildimg
make deploy-bink
make e2e V=1 RUN='TestUpdateReboot\|TestTagResolution'

watch events in second terminal: kubectl get events.events.k8s.io -A --watch

closes: #101

[HarshwardhanPatil07]

PTAL @Johan-Liebert1 @ptalgulk01 @alicefr

[HarshwardhanPatil07]

@ptalgulk01 Thanks. added the changes

[HarshwardhanPatil07]

rebase

[alicefr]

@HarshwardhanPatil07 can we split the commit 161e5e7 into mulitple. At least one per event type, like one for the draining stalls, one for the node events and one for the degraded nodes.

[alicefr]

I'm really not a big fan of truncate the string. I think instead we should use an interface and struct with well defined fields and functions that can shorten the string. Something like:

 // Event note types — each knows its own max rendered length.
  type PoolImageUpdateNote struct {
      ImageRef       string // max ~255 (OCI spec)
      NewDigest      string // fixed 71 (sha256:64hex)
      PreviousDigest string // fixed 71
  }

  func (n PoolImageUpdateNote) Note() string {
      return fmt.Sprintf("Image tag %s resolved to new digest %s (previously %s)",
          n.ImageRef, shortDigest(n.NewDigest), shortDigest(n.PreviousDigest))
  }

  type PoolRolloutStartedNote struct {
      TargetDigest string
  }

  func (n PoolRolloutStartedNote) Note() string {
      return fmt.Sprintf("Rollout started toward digest %s", shortDigest(n.TargetDigest))
  }

  // Interface all event notes implement.
  type EventNote interface {
      Note() string
  }

  func shortDigest(d string) string {
      if len(d) > 19 { // "sha256:" + 12 hex
          return d[:19]
      }
      return d
  }

and then the recordEventf becomes:

func (r *BootcNodePoolReconciler) recordEvent(
      regarding, related runtime.Object,
      eventType, reason, action string,
      note EventNote,) 
{
      r.Recorder.Eventf(regarding, related, eventType, reason, action, "%s", note.Note())
}

[alicefr]

Should we also add when the node becomes idle again?

[HarshwardhanPatil07]

added a nodeIdleNote "Node is up to date" event emitted when a node returns to idle

[HarshwardhanPatil07]

PTAL @alicefr