[Feature] Respect ToBeCleanedServers in Agency (#1146)

CHANGELOG.md

@@ -8,6 +8,7 @@
 - (Feature) ID ServerGroup
 - (Bugfix) Propagate Lifecycle Mount
 - (Feature) PVC Member Status info
+- (Feature) Respect ToBeCleanedServers in Agency
 
 ## [1.2.19](https://github.com/arangodb/kube-arangodb/tree/1.2.19) (2022-10-05)
 - (Bugfix) Prevent changes when UID is wrong

pkg/deployment/agency/target.go

@@ -30,7 +30,8 @@ type StateTarget struct {
 
 	// Servers Section
 
-	CleanedServers Servers `json:"CleanedServers,omitempty"`
+	CleanedServers     Servers `json:"CleanedServers,omitempty"`
+	ToBeCleanedServers Servers `json:"ToBeCleanedServers,omitempty"`
 
 	// HotBackup section
 

pkg/deployment/reconcile/plan_builder_scale.go

@@ -92,7 +92,7 @@ func (r *Reconciler) createScalePlan(status api.DeploymentStatus, members api.Me
 			Debug("Creating scale-up plan")
 	} else if len(members) > count {
 		// Note, we scale down 1 member at a time
-		if m, err := members.SelectMemberToRemove(getCleanedServer(context), topologyMissingMemberToRemoveSelector(status.Topology), topologyAwarenessMemberToRemoveSelector(group, status.Topology)); err != nil {
+		if m, err := members.SelectMemberToRemove(getCleanedServer(context), getToBeCleanedServer(context), topologyMissingMemberToRemoveSelector(status.Topology), topologyAwarenessMemberToRemoveSelector(group, status.Topology)); err != nil {
 			r.planLogger.Err(err).Str("role", group.AsRole()).Warn("Failed to select member to remove")
 		} else {
 			ready, message := groupReadyForRestart(context, status, m, group)
@@ -180,6 +180,19 @@ func getCleanedServer(ctx reconciler.ArangoAgencyGet) api.MemberToRemoveSelector
 	}
 }
 
+func getToBeCleanedServer(ctx reconciler.ArangoAgencyGet) api.MemberToRemoveSelector {
+	return func(m api.MemberStatusList) (string, error) {
+		if a, ok := ctx.GetAgencyCache(); ok {
+			for _, member := range m {
+				if a.Target.ToBeCleanedServers.Contains(agency.Server(member.ID)) {
+					return member.ID, nil
+				}
+			}
+		}
+		return "", nil
+	}
+}
+
 func (r *Reconciler) scaleDownCandidate(ctx context.Context, apiObject k8sutil.APIObject,
 	spec api.DeploymentSpec, status api.DeploymentStatus,
 	context PlanBuilderContext) api.Plan {