Merge pull request k8snetworkplumbingwg#455 from SchSeba/fix_lock_race

Fix race condition in leader election for OCP

pkg/daemon/daemon.go

@@ -507,18 +507,22 @@ func (dn *Daemon) nodeStateSyncHandler() error {
 				go dn.getDrainLock(ctx, done)
 				<-done
 			}
+		}
 
-			if dn.openshiftContext.IsOpenshiftCluster() && !dn.openshiftContext.IsHypershift() {
-				glog.Infof("nodeStateSyncHandler(): pause MCP")
-				if err := dn.pauseMCP(); err != nil {
-					return err
-				}
+		if dn.openshiftContext.IsOpenshiftCluster() && !dn.openshiftContext.IsHypershift() {
+			glog.Infof("nodeStateSyncHandler(): pause MCP")
+			if err := dn.pauseMCP(); err != nil {
+				return err
 			}
 		}
 
-		glog.Info("nodeStateSyncHandler(): drain node")
-		if err := dn.drainNode(); err != nil {
-			return err
+		if dn.disableDrain {
+			glog.Info("nodeStateSyncHandler(): disable drain is true skipping drain")
+		} else {
+			glog.Info("nodeStateSyncHandler(): drain node")
+			if err := dn.drainNode(); err != nil {
+				return err
+			}
 		}
 	}
 
@@ -578,17 +582,14 @@ func (dn *Daemon) nodeHasAnnotation(annoKey string, value string) bool {
 	return false
 }
 
+// isNodeDraining: check if the node is draining
+// both Draining and MCP paused labels will return true
 func (dn *Daemon) isNodeDraining() bool {
 	anno, ok := dn.node.Annotations[annoKey]
 	if !ok {
 		return false
 	}
 
-	if dn.openshiftContext.IsOpenshiftCluster() && !dn.openshiftContext.IsHypershift() {
-		// for openshift cluster draining should be true only if the annotation has MCP paused
-		return anno == annoMcpPaused
-	}
-
 	return anno == annoDraining || anno == annoMcpPaused
 }
 
@@ -895,11 +896,6 @@ func (dn *Daemon) pauseMCP() error {
 }
 
 func (dn *Daemon) drainNode() error {
-	if dn.disableDrain {
-		glog.Info("drainNode(): disable drain is true skipping drain")
-		return nil
-	}
-
 	glog.Info("drainNode(): Update prepared")
 	var err error
 

pkg/daemon/daemon_test.go

@@ -275,7 +275,7 @@ SUBSYSTEM=="net", ACTION=="add|move", ATTRS{phys_switch_id}!="", ATTR{phys_port_
 			Expect(sut.isNodeDraining()).To(BeFalse())
 
 			sut.node.Annotations["sriovnetwork.openshift.io/state"] = "Draining"
-			Expect(sut.isNodeDraining()).To(BeFalse())
+			Expect(sut.isNodeDraining()).To(BeTrue())
 
 			sut.node.Annotations["sriovnetwork.openshift.io/state"] = "Draining_MCP_Paused"
 			Expect(sut.isNodeDraining()).To(BeTrue())