nfd-master: implement --prune flag

A new sub-command like flag for cleaning up a cluster. When --prune is
specified nfd-master removes all NFD related labels, annotations and
extended resources from all nodes of the cluster and exits.

This should help undeployment of NFD and be useful for development.

cmd/nfd-master/main.go

@@ -63,7 +63,7 @@ func argsParse(argv []string) (master.Args, error) {
 	usage := fmt.Sprintf(`%s.
 
   Usage:
-  %s [--no-publish] [--label-whitelist=<pattern>] [--port=<port>]
+  %s [--prune] [--no-publish] [--label-whitelist=<pattern>] [--port=<port>]
      [--ca-file=<path>] [--cert-file=<path>] [--key-file=<path>]
      [--verify-node-name] [--extra-label-ns=<list>] [--resource-labels=<list>]
   %s -h | --help
@@ -72,6 +72,8 @@ func argsParse(argv []string) (master.Args, error) {
   Options:
   -h --help                       Show this screen.
   --version                       Output version and exit.
+  --prune                         Prune all NFD related attributes from all nodes
+                                  of the cluster and exit.
   --port=<port>                   Port on which to listen for connections.
                                   [Default: 8080]
   --ca-file=<path>                Root certificate for verifying connections
@@ -119,6 +121,7 @@ func argsParse(argv []string) (master.Args, error) {
 	args.VerifyNodeName = arguments["--verify-node-name"].(bool)
 	args.ExtraLabelNs = strings.Split(arguments["--extra-label-ns"].(string), ",")
 	args.ResourceLabels = strings.Split(arguments["--resource-labels"].(string), ",")
+	args.Prune = arguments["--prune"].(bool)
 
 	return args, nil
 }

pkg/apihelper/apihelpers.go

@@ -29,6 +29,9 @@ type APIHelpers interface {
 	// GetNode returns the Kubernetes node on which this container is running.
 	GetNode(*k8sclient.Clientset, string) (*api.Node, error)
 
+	// GetNodes returns all the nodes in the cluster
+	GetNodes(*k8sclient.Clientset) (*api.NodeList, error)
+
 	// UpdateNode updates the node via the API server using a client.
 	UpdateNode(*k8sclient.Clientset, *api.Node) error
 

pkg/apihelper/k8shelpers.go

@@ -53,6 +53,10 @@ func (h K8sHelpers) GetNode(cli *k8sclient.Clientset, nodeName string) (*api.Nod
 	return node, nil
 }
 
+func (h K8sHelpers) GetNodes(cli *k8sclient.Clientset) (*api.NodeList, error) {
+	return cli.CoreV1().Nodes().List(meta_v1.ListOptions{})
+}
+
 func (h K8sHelpers) UpdateNode(c *k8sclient.Clientset, n *api.Node) error {
 	// Send the updated node to the apiserver.
 	_, err := c.CoreV1().Nodes().Update(n)

pkg/apihelper/mock_APIHelpers.go

@@ -62,6 +62,29 @@ func (_m *MockAPIHelpers) GetNode(_a0 *kubernetes.Clientset, _a1 string) (*v1.No
 	return r0, r1
 }
 
+// GetNodes provides a mock function with given fields: _a0
+func (_m *MockAPIHelpers) GetNodes(_a0 *kubernetes.Clientset) (*v1.NodeList, error) {
+	ret := _m.Called(_a0)
+
+	var r0 *v1.NodeList
+	if rf, ok := ret.Get(0).(func(*kubernetes.Clientset) *v1.NodeList); ok {
+		r0 = rf(_a0)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*v1.NodeList)
+		}
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(*kubernetes.Clientset) error); ok {
+		r1 = rf(_a0)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // PatchStatus provides a mock function with given fields: _a0, _a1, _a2
 func (_m *MockAPIHelpers) PatchStatus(_a0 *kubernetes.Clientset, _a1 string, _a2 interface{}) error {
 	ret := _m.Called(_a0, _a1, _a2)

pkg/nfd-master/nfd-master.go

@@ -73,6 +73,7 @@ type Args struct {
 	LabelWhiteList *regexp.Regexp
 	NoPublish      bool
 	Port           int
+	Prune          bool
 	VerifyNodeName bool
 	ResourceLabels []string
 }
@@ -84,9 +85,10 @@ type NfdMaster interface {
 }
 
 type nfdMaster struct {
-	args   Args
-	server *grpc.Server
-	ready  chan bool
+	args      Args
+	server    *grpc.Server
+	ready     chan bool
+	apihelper apihelper.APIHelpers
 }
 
 // statusOp is a json marshaling helper used for patching node status
@@ -121,6 +123,9 @@ func NewNfdMaster(args Args) (NfdMaster, error) {
 		}
 	}
 
+	// Initialize Kubernetes API helpers
+	nfd.apihelper = apihelper.K8sHelpers{}
+
 	return nfd, nil
 }
 
@@ -130,11 +135,12 @@ func (m *nfdMaster) Run() error {
 	stdoutLogger.Printf("Node Feature Discovery Master %s", version.Get())
 	stdoutLogger.Printf("NodeName: '%s'", nodeName)
 
-	// Initialize Kubernetes API helpers
-	helper := apihelper.APIHelpers(apihelper.K8sHelpers{})
+	if m.args.Prune {
+		return m.prune()
+	}
 
 	if !m.args.NoPublish {
-		err := updateMasterNode(helper)
+		err := updateMasterNode(m.apihelper)
 		if err != nil {
 			return fmt.Errorf("failed to update master node: %v", err)
 		}
@@ -176,7 +182,7 @@ func (m *nfdMaster) Run() error {
 		serverOpts = append(serverOpts, grpc.Creds(credentials.NewTLS(tlsConfig)))
 	}
 	m.server = grpc.NewServer(serverOpts...)
-	pb.RegisterLabelerServer(m.server, &labelerServer{args: m.args, apiHelper: helper})
+	pb.RegisterLabelerServer(m.server, &labelerServer{args: m.args, apiHelper: m.apihelper})
 	stdoutLogger.Printf("gRPC server serving on port: %d", m.args.Port)
 	return m.server.Serve(lis)
 }
@@ -201,6 +207,46 @@ func (m *nfdMaster) WaitForReady(timeout time.Duration) bool {
 	return false
 }
 
+// Prune erases all NFD related properties from the node objects of the cluster.
+func (m *nfdMaster) prune() error {
+	cli, err := m.apihelper.GetClient()
+	if err != nil {
+		return err
+	}
+
+	nodes, err := m.apihelper.GetNodes(cli)
+	if err != nil {
+		return err
+	}
+
+	for _, node := range nodes.Items {
+		stdoutLogger.Printf("pruning node %q...", node.Name)
+
+		// Prune labels and extended resources
+		err := updateNodeFeatures(m.apihelper, node.Name, Labels{}, Annotations{}, ExtendedResources{})
+		if err != nil {
+			return fmt.Errorf("failed to prune labels from node %q: %v", node.Name, err)
+		}
+
+		// Prune annotations
+		node, err := m.apihelper.GetNode(cli, node.Name)
+		if err != nil {
+			return err
+		}
+		for a := range node.Annotations {
+			if strings.HasPrefix(a, AnnotationNs) {
+				delete(node.Annotations, a)
+			}
+		}
+		err = m.apihelper.UpdateNode(cli, node)
+		if err != nil {
+			return fmt.Errorf("failed to prune annotations from node %q: %v", node.Name, err)
+		}
+
+	}
+	return nil
+}
+
 // Advertise NFD master information
 func updateMasterNode(helper apihelper.APIHelpers) error {
 	cli, err := helper.GetClient()