Enable Orchestrator maintenance mode during reparents

go/vt/vttablet/tabletmanager/rpc_replication.go

@@ -287,6 +287,17 @@ func (agent *ActionAgent) DemoteMaster(ctx context.Context) (string, error) {
 	}
 	defer agent.unlock()
 
+	// Tell Orchestrator we're stopped on purpose the demotion.
+	// This is a best effort task, so run it in a goroutine.
+	go func() {
+		if agent.orc == nil {
+			return
+		}
+		if err := agent.orc.BeginMaintenance(agent.Tablet(), "vttablet has been told to DemoteMaster"); err != nil {
+			log.Warningf("Orchestrator BeginMaintenance failed: %v", err)
+		}
+	}()
+
 	// Set the server read-only. Note all active connections are not
 	// affected.
 	if err := agent.MysqlDaemon.SetReadOnly(true); err != nil {
@@ -399,6 +410,21 @@ func (agent *ActionAgent) setMasterLocked(ctx context.Context, parentAlias *topo
 		return err
 	}
 
+	// If this tablet used to be a master, end orchestrator maintenance after we are connected to the new master.
+	// This is a best effort operation, so it should happen in a goroutine
+	if agent.Tablet().Type == topodatapb.TabletType_MASTER {
+		defer func() {
+			go func() {
+				if agent.orc == nil {
+					return
+				}
+				if err := agent.orc.EndMaintenance(agent.Tablet()); err != nil {
+					log.Warningf("Orchestrator EndMaintenance failed: %v", err)
+				}
+			}()
+		}()
+	}
+
 	// See if we were replicating at all, and should be replicating
 	wasReplicating := false
 	shouldbeReplicating := false