Enable shared filesystem support

(cherry picked from commit 974c9db7)

provisioner.go

@@ -74,6 +74,7 @@ type NodePathMapData struct {
 type ConfigData struct {
 	NodePathMap []*NodePathMapData `json:"nodePathMap,omitempty"`
 	CmdTimeoutSeconds int `json:"cmdTimeoutSeconds,omitempty"`
+	SharedFileSystemPath string             `json:"sharedFileSystemPath,omitempty"`
 }
 
 type NodePathMap struct {
@@ -83,6 +84,7 @@ type NodePathMap struct {
 type Config struct {
 	NodePathMap       map[string]*NodePathMap
 	CmdTimeoutSeconds int
+	SharedFileSystemPath string
 }
 
 func NewProvisioner(stopCh chan struct{}, kubeClient *clientset.Clientset,
@@ -170,6 +172,15 @@ func (p *LocalPathProvisioner) getRandomPathOnNode(node string) (string, error)
 	}
 
 	c := p.config
+	sharedFS, err := p.isSharedFilesystem()
+	if err != nil {
+		return "", err
+	}
+	if sharedFS {
+		// we are ignoring 'node' and returning shared FS path
+		return c.SharedFileSystemPath, nil
+	}
+	// we are working with local FS
 	npMap := c.NodePathMap[node]
 	if npMap == nil {
 		npMap = c.NodePathMap[NodeDefaultNonListedNodes]
@@ -189,8 +200,38 @@ func (p *LocalPathProvisioner) getRandomPathOnNode(node string) (string, error)
 	return path, nil
 }
 
+func (p *LocalPathProvisioner) isSharedFilesystem() (bool, error) {
+	p.configMutex.RLock()
+	defer p.configMutex.RUnlock()
+
+	if p.config == nil {
+		return false, fmt.Errorf("no valid config available")
+	}
+
+	c := p.config
+	if (c.SharedFileSystemPath != "") && (len(c.NodePathMap) != 0) {
+		return false, fmt.Errorf("both nodePathMap and sharedFileSystemPath are defined. Please make sure only one is in use")
+	}
+
+	if len(c.NodePathMap) != 0 {
+		return false, nil
+	}
+
+	if c.SharedFileSystemPath != "" {
+		return true, nil
+	}
+
+	return false, fmt.Errorf("both nodePathMap and sharedFileSystemPath are unconfigured")
+}
+
 func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v1.PersistentVolume, error) {
 	pvc := opts.PVC
+	node := opts.SelectedNode
+	sharedFS, err := p.isSharedFilesystem()
+	if err != nil {
+		return nil, err
+	}
+	if !sharedFS {
 		if pvc.Spec.Selector != nil {
 			return nil, fmt.Errorf("claim.Spec.Selector is not supported")
 		}
@@ -199,12 +240,17 @@ func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v
 				return nil, fmt.Errorf("Only support ReadWriteOnce access mode")
 			}
 		}
-	node := opts.SelectedNode
-	if opts.SelectedNode == nil {
+		if node == nil {
 			return nil, fmt.Errorf("configuration error, no node was specified")
 		}
+	}
 
-	basePath, err := p.getRandomPathOnNode(node.Name)
+	nodeName := ""
+	if node != nil {
+		// This clause works only with sharedFS
+		nodeName = node.Name
+	}
+	basePath, err := p.getRandomPathOnNode(nodeName)
 	if err != nil {
 		return nil, err
 	}
@@ -213,7 +259,11 @@ func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v
 	folderName := strings.Join([]string{name, opts.PVC.Namespace, opts.PVC.Name}, "_")
 
 	path := filepath.Join(basePath, folderName)
-	logrus.Infof("Creating volume %v at %v:%v", name, node.Name, path)
+	if nodeName == "" {
+		logrus.Infof("Creating volume %v at %v", name, path)
+	} else {
+		logrus.Infof("Creating volume %v at %v:%v", name, nodeName, path)
+	}
 
 	storage := pvc.Spec.Resources.Requests[v1.ResourceName(v1.ResourceStorage)]
 	provisionCmd := []string{"/bin/sh", "/script/setup"}
@@ -222,7 +272,7 @@ func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v
 		Path:        path,
 		Mode:        *pvc.Spec.VolumeMode,
 		SizeInBytes: storage.Value(),
-		Node:        node.Name,
+		Node:        nodeName,
 	}); err != nil {
 		return nil, err
 	}
@@ -246,24 +296,17 @@ func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v
 		}
 	}
 
+	var nodeAffinity *v1.VolumeNodeAffinity
+	if sharedFS {
+		// If the same filesystem is mounted across all nodes, we don't need
+		// affinity, as path is accessible from any node
+		nodeAffinity = nil
+	} else {
 		valueNode, ok := node.GetLabels()[KeyNode]
 		if !ok {
-		valueNode = node.Name
+			valueNode = nodeName
 		}
-
-	return &v1.PersistentVolume{
-		ObjectMeta: metav1.ObjectMeta{
-			Name: name,
-		},
-		Spec: v1.PersistentVolumeSpec{
-			PersistentVolumeReclaimPolicy: *opts.StorageClass.ReclaimPolicy,
-			AccessModes:                   pvc.Spec.AccessModes,
-			VolumeMode:                    &fs,
-			Capacity: v1.ResourceList{
-				v1.ResourceName(v1.ResourceStorage): pvc.Spec.Resources.Requests[v1.ResourceName(v1.ResourceStorage)],
-			},
-			PersistentVolumeSource: pvs,
-			NodeAffinity: &v1.VolumeNodeAffinity{
+		nodeAffinity = &v1.VolumeNodeAffinity{
 			Required: &v1.NodeSelector{
 				NodeSelectorTerms: []v1.NodeSelectorTerm{
 					{
@@ -279,7 +322,21 @@ func (p *LocalPathProvisioner) Provision(opts pvController.ProvisionOptions) (*v
 					},
 				},
 			},
+		}
+	}
+	return &v1.PersistentVolume{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: name,
+		},
+		Spec: v1.PersistentVolumeSpec{
+			PersistentVolumeReclaimPolicy: *opts.StorageClass.ReclaimPolicy,
+			AccessModes:                   pvc.Spec.AccessModes,
+			VolumeMode:                    &fs,
+			Capacity: v1.ResourceList{
+				v1.ResourceName(v1.ResourceStorage): pvc.Spec.Resources.Requests[v1.ResourceName(v1.ResourceStorage)],
 			},
+			PersistentVolumeSource: pvs,
+			NodeAffinity: nodeAffinity,
 		},
 	}, nil
 }
@@ -293,7 +350,11 @@ func (p *LocalPathProvisioner) Delete(pv *v1.PersistentVolume) (err error) {
 		return err
 	}
 	if pv.Spec.PersistentVolumeReclaimPolicy != v1.PersistentVolumeReclaimRetain {
+		if node == "" {
+			logrus.Infof("Deleting volume %v at %v", pv.Name, path)
+		} else {
 			logrus.Infof("Deleting volume %v at %v:%v", pv.Name, node, path)
+		}
 		storage := pv.Spec.Capacity[v1.ResourceName(v1.ResourceStorage)]
 		cleanupCmd := []string{"/bin/sh", "/script/teardown"}
 		if err := p.createHelperPod(ActionTypeDelete, cleanupCmd, volumeOptions{
@@ -326,6 +387,18 @@ func (p *LocalPathProvisioner) getPathAndNodeForPV(pv *v1.PersistentVolume) (pat
 		return "", "", fmt.Errorf("no path set")
 	}
 
+	sharedFS, err := p.isSharedFilesystem()
+	if err != nil {
+		return "", "", err
+	}
+
+	if sharedFS {
+		// We don't have affinity and can use any node
+		return path, "", nil
+	}
+
+	// Dealing with local filesystem
+
 	nodeAffinity := pv.Spec.NodeAffinity
 	if nodeAffinity == nil {
 		return "", "", fmt.Errorf("no NodeAffinity set")
@@ -368,7 +441,11 @@ func (p *LocalPathProvisioner) createHelperPod(action ActionType, cmd []string,
 	defer func() {
 		err = errors.Wrapf(err, "failed to %v volume %v", action, o.Name)
 	}()
-	if o.Name == "" || o.Path == "" || o.Node == "" {
+	sharedFS, err := p.isSharedFilesystem()
+	if err != nil {
+		return err
+	}
+	if o.Name == "" || o.Path == "" || (!sharedFS && o.Node == "") {
 		return fmt.Errorf("invalid empty name or path or node")
 	}
 	if !filepath.IsAbs(o.Path) {
@@ -438,7 +515,9 @@ func (p *LocalPathProvisioner) createHelperPod(action ActionType, cmd []string,
 		helperPod.Name = helperPod.Name[:HelperPodNameMaxLength]
 	}
 	helperPod.Namespace = p.namespace
+	if o.Node != "" {
 		helperPod.Spec.NodeName = o.Node
+	}
 	helperPod.Spec.ServiceAccountName = p.serviceAccountName
 	helperPod.Spec.RestartPolicy = v1.RestartPolicyNever
 	helperPod.Spec.Tolerations = append(helperPod.Spec.Tolerations, lpvTolerations...)
@@ -478,7 +557,11 @@ func (p *LocalPathProvisioner) createHelperPod(action ActionType, cmd []string,
 		return fmt.Errorf("create process timeout after %v seconds", p.config.CmdTimeoutSeconds)
 	}
 
+	if o.Node == "" {
+		logrus.Infof("Volume %v has been %vd on %v", o.Name, action, o.Path)
+	} else {
 		logrus.Infof("Volume %v has been %vd on %v:%v", o.Name, action, o.Node, o.Path)
+	}
 	return nil
 }
 
@@ -534,6 +617,7 @@ func canonicalizeConfig(data *ConfigData) (cfg *Config, err error) {
 		err = errors.Wrapf(err, "config canonicalization failed")
 	}()
 	cfg = &Config{}
+	cfg.SharedFileSystemPath = data.SharedFileSystemPath
 	cfg.NodePathMap = map[string]*NodePathMap{}
 	for _, n := range data.NodePathMap {
 		if cfg.NodePathMap[n.Node] != nil {