OCPEDGE-998: fix: avoid restart of vgmanager on config reload

cmd/vgmanager/vgmanager.go

@@ -18,6 +18,7 @@ package vgmanager
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"os/signal"
@@ -42,11 +43,11 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/topolvm/topolvm"
 	"github.com/topolvm/topolvm/pkg/controller"
-
 	"github.com/topolvm/topolvm/pkg/driver"
 	topoLVMD "github.com/topolvm/topolvm/pkg/lvmd"
 	"github.com/topolvm/topolvm/pkg/runners"
 	"google.golang.org/grpc"
+	"k8s.io/utils/ptr"
 
 	"k8s.io/apimachinery/pkg/runtime"
 	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
@@ -70,6 +71,8 @@ const (
 	DefaultProbeAddr       = ":8081"
 )
 
+var ErrConfigModified = errors.New("lvmd config file is modified")
+
 type Options struct {
 	Scheme   *runtime.Scheme
 	SetupLog logr.Logger
@@ -101,7 +104,9 @@ func NewCmd(opts *Options) *cobra.Command {
 }
 
 func run(cmd *cobra.Command, _ []string, opts *Options) error {
-	ctx, cancel := context.WithCancel(cmd.Context())
+	ctx, cancelWithCause := context.WithCancelCause(cmd.Context())
+	defer cancelWithCause(nil)
+	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM)
 	defer cancel()
 
 	lvm := lvm.NewDefaultHostLVM()
@@ -138,6 +143,7 @@ func run(cmd *cobra.Command, _ []string, opts *Options) error {
 				operatorNamespace: {},
 			},
 		},
+		GracefulShutdownTimeout: ptr.To(time.Duration(-1)),
 	})
 	if err != nil {
 		return fmt.Errorf("unable to start manager: %w", err)
@@ -203,7 +209,6 @@ func run(cmd *cobra.Command, _ []string, opts *Options) error {
 		NodeName:      nodeName,
 		Namespace:     operatorNamespace,
 		Filters:       filter.DefaultFilters,
-		Shutdown:      cancel,
 	}).SetupWithManager(mgr); err != nil {
 		return fmt.Errorf("unable to create controller VGManager: %w", err)
 	}
@@ -212,74 +217,79 @@ func run(cmd *cobra.Command, _ []string, opts *Options) error {
 		return fmt.Errorf("unable to set up health check: %w", err)
 	}
 
-	c := make(chan os.Signal, 2)
-	signal.Notify(c, []os.Signal{os.Interrupt, syscall.SIGTERM}...)
-	go func() {
-		<-c
-		cancel()
-		<-c
-		os.Exit(1) // second signal. Exit directly.
-	}()
-
 	// Create new watcher.
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
 		return fmt.Errorf("unable to set up file watcher: %w", err)
 	}
 	defer watcher.Close()
-
-	// Start listening for events.
-	go func() {
-		fileNotExist := false
-		for {
-			// check if file exists, otherwise the watcher errors
-			_, err := os.Lstat(lvmd.DefaultFileConfigPath)
-			if err != nil {
-				if os.IsNotExist(err) {
-					time.Sleep(100 * time.Millisecond)
-					fileNotExist = true
-				} else {
-					opts.SetupLog.Error(err, "unable to check if lvmd config file exists")
-				}
-			} else {
-				// This handles the first time the file is created through the configmap
-				if fileNotExist {
-					cancel()
-				}
-				err = watcher.Add(lvmd.DefaultFileConfigPath)
-				if err != nil {
-					opts.SetupLog.Error(err, "unable to add file path to watcher")
-				}
-				break
-			}
-		}
-		for {
-			select {
-			case event, ok := <-watcher.Events:
-				if !ok {
-					return
-				}
-				if event.Has(fsnotify.Write) || event.Has(fsnotify.Remove) || event.Has(fsnotify.Chmod) {
-					opts.SetupLog.Info("lvmd config file is modified", "eventName", event.Name)
-					cancel()
-				}
-			case err, ok := <-watcher.Errors:
-				if !ok {
-					return
-				}
-				opts.SetupLog.Error(err, "file watcher error")
-			}
-		}
-	}()
+	// Start listening for events on TopoLVM files.
+	go watchTopoLVMAndNotify(opts, cancelWithCause, watcher)
 
 	opts.SetupLog.Info("starting manager")
 	if err := mgr.Start(ctx); err != nil {
 		return fmt.Errorf("problem running manager: %w", err)
 	}
 
+	if errors.Is(context.Cause(ctx), ErrConfigModified) {
+		opts.SetupLog.Info("restarting controller due to modified configuration")
+		return run(cmd, nil, opts)
+	} else if err := ctx.Err(); err != nil {
+		opts.SetupLog.Error(err, "exiting abnormally")
+		os.Exit(1)
+	}
+
 	return nil
 }
 
+// watchTopoLVMAndNotify watches for changes to the lvmd config file and cancels the context if it changes.
+// This is used to restart the manager when the lvmd config file changes.
+// This is a blocking function and should be run in a goroutine.
+// If the directory does not exist, it will be created to make it possible to watch for changes.
+// If the watch determines that the lvmd config file has been modified, it will cancel the context with the ErrConfigModified error.
+func watchTopoLVMAndNotify(opts *Options, cancelWithCause context.CancelCauseFunc, watcher *fsnotify.Watcher) {
+	// check if file exists, otherwise the watcher errors
+	fi, err := os.Stat(lvmd.DefaultFileConfigDir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			if err := os.MkdirAll(lvmd.DefaultFileConfigDir, 0755); err != nil {
+				opts.SetupLog.Error(err, "unable to create lvmd config directory when it did not exist before")
+			}
+		} else {
+			opts.SetupLog.Error(err, "unable to check if lvmd config directory exists")
+			cancelWithCause(err)
+		}
+	} else if !fi.IsDir() {
+		opts.SetupLog.Error(err, "expected lvmd config directory is not a directory")
+		cancelWithCause(err)
+	}
+
+	err = watcher.Add(lvmd.DefaultFileConfigDir)
+	if err != nil {
+		opts.SetupLog.Error(err, "unable to add file path to watcher")
+	}
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+			if event.Name != lvmd.DefaultFileConfigPath {
+				continue
+			}
+			if event.Has(fsnotify.Write) || event.Has(fsnotify.Remove) || event.Has(fsnotify.Chmod) {
+				opts.SetupLog.Info("lvmd config file is modified", "eventName", event.Name)
+				cancelWithCause(fmt.Errorf("%w: %s", ErrConfigModified, event.Name))
+			}
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				return
+			}
+			opts.SetupLog.Error(err, "file watcher error")
+		}
+	}
+}
+
 func loadConfFile(ctx context.Context, config *lvmd.Config, cfgFilePath string) error {
 	b, err := os.ReadFile(cfgFilePath)
 	if err != nil {

go.mod

@@ -45,7 +45,7 @@ require (
 	sigs.k8s.io/yaml v1.4.0
 )
 
-replace github.com/topolvm/topolvm => github.com/openshift/topolvm v0.15.3-0.20240314121823-1339f4f8b9ae
+replace github.com/topolvm/topolvm => github.com/openshift/topolvm v0.15.3-0.20240321104545-ab31b05c1b85
 
 require (
 	github.com/Masterminds/goutils v1.1.1 // indirect

go.sum

@@ -155,8 +155,8 @@ github.com/openshift/client-go v0.0.0-20240312121557-60dd5f9fbf8d h1:vdrC3QYkFcs
 github.com/openshift/client-go v0.0.0-20240312121557-60dd5f9fbf8d/go.mod h1:Y5Hp789dTrF6Fq8cA5YQlpwffmlLy8mc2un/CY0cg7Q=
 github.com/openshift/library-go v0.0.0-20240312152318-4109a9e7a437 h1:xMflL80gT2cXxnmDkR8QLZCbfh/x38jV5XOfLiNlsLE=
 github.com/openshift/library-go v0.0.0-20240312152318-4109a9e7a437/go.mod h1:ePlaOqUiPplRc++6aYdMe+2FmXb2xTNS9Nz5laG2YmI=
-github.com/openshift/topolvm v0.15.3-0.20240314121823-1339f4f8b9ae h1:j6Y1iy4+Ml7QM3psiAeUtLUY+mFHfdi7xolnNtwz8fI=
-github.com/openshift/topolvm v0.15.3-0.20240314121823-1339f4f8b9ae/go.mod h1:BfEw9thAo64c4xYejdbGYPOHPWhAKIaGwq72gP2Lqkc=
+github.com/openshift/topolvm v0.15.3-0.20240321104545-ab31b05c1b85 h1:LdqfViDjjcIIgidKm+7lIRlpA49XZh9Qfjym4ab4CH8=
+github.com/openshift/topolvm v0.15.3-0.20240321104545-ab31b05c1b85/go.mod h1:sp/P6O6+7is1dnV6am+yk+djRxxfcOPyzW4Bi2CfEyU=
 github.com/operator-framework/api v0.22.0 h1:UZSn+iaQih4rCReezOnWTTJkMyawwV5iLnIItaOzytY=
 github.com/operator-framework/api v0.22.0/go.mod h1:p/7YDbr+n4fmESfZ47yLAV1SvkfE6NU2aX8KhcfI0GA=
 github.com/pelletier/go-toml v1.9.5 h1:4yBQzkHv+7BHq2PQUZF3Mx0IYxG7LsP222s7Agd3ve8=

internal/controllers/vgmanager/controller.go

@@ -95,7 +95,6 @@ type Reconciler struct {
 	NodeName  string
 	Namespace string
 	Filters   func(*lvmv1alpha1.LVMVolumeGroup) filter.Filters
-	Shutdown  context.CancelFunc
 }
 
 func (r *Reconciler) getFinalizer() string {
@@ -392,11 +391,9 @@ func (r *Reconciler) updateLVMDConfigAfterReconcile(
 		if err := r.LVMD.Save(ctx, newCFG); err != nil {
 			return fmt.Errorf("failed to update lvmd config file to update volume group %s: %w", volumeGroup.GetName(), err)
 		}
-		msg := "updated lvmd config with new deviceClasses, now restarting.."
+		msg := "updated lvmd config with new deviceClasses"
 		logger.Info(msg)
 		r.NormalEvent(ctx, volumeGroup, EventReasonLVMDConfigUpdated, msg)
-
-		r.Shutdown()
 	}
 	return nil
 }

internal/controllers/vgmanager/controller_test.go

@@ -302,14 +302,8 @@ func testMockedBlockDeviceOnHost(ctx context.Context) {
 	})
 
 	By("triggering the next reconciliation after the creation of the thin pool", func() {
-		cancelled := false
-		cancelable := func() {
-			cancelled = true
-		}
-		instances.Reconciler.Shutdown = cancelable
 		_, err := instances.Reconciler.Reconcile(ctx, reconcile.Request{NamespacedName: client.ObjectKeyFromObject(vg)})
 		Expect(err).ToNot(HaveOccurred())
-		Eventually(ctx, func() bool { return cancelled }).Should(BeTrue())
 	})
 
 	By("verifying the lvmd config generation", func() {

internal/controllers/vgmanager/lvmd/lvmd.go

@@ -21,7 +21,8 @@ type ThinPoolConfig = lvmd.ThinPoolConfig
 var TypeThin = lvmd.TypeThin
 
 const (
-	DefaultFileConfigPath = "/etc/topolvm/lvmd.yaml"
+	DefaultFileConfigDir  = "/etc/topolvm"
+	DefaultFileConfigPath = DefaultFileConfigDir + "/lvmd.yaml"
 	maxReadLength         = 2 * 1 << 20 // 2MB
 )
 

vendor/modules.txt

@@ -374,7 +374,7 @@ github.com/stretchr/objx
 ## explicit; go 1.17
 github.com/stretchr/testify/assert
 github.com/stretchr/testify/mock
-# github.com/topolvm/topolvm v0.27.1-0.20240306010159-8c6c91dc8b7f => github.com/openshift/topolvm v0.15.3-0.20240314121823-1339f4f8b9ae
+# github.com/topolvm/topolvm v0.27.1-0.20240306010159-8c6c91dc8b7f => github.com/openshift/topolvm v0.15.3-0.20240321104545-ab31b05c1b85
 ## explicit; go 1.20
 github.com/topolvm/topolvm
 github.com/topolvm/topolvm/api/legacy/v1
@@ -1287,4 +1287,4 @@ sigs.k8s.io/structured-merge-diff/v4/value
 ## explicit; go 1.12
 sigs.k8s.io/yaml
 sigs.k8s.io/yaml/goyaml.v2
-# github.com/topolvm/topolvm => github.com/openshift/topolvm v0.15.3-0.20240314121823-1339f4f8b9ae
+# github.com/topolvm/topolvm => github.com/openshift/topolvm v0.15.3-0.20240321104545-ab31b05c1b85