mon: fix mon failover on path change

This PR fails over mon when the mon path is changed from hostPath to PVC or vice versa

Signed-off-by: sp98 <sapillai@redhat.com>
(cherry picked from commit 4b6fd89365)

pkg/operator/ceph/cluster/mon/health.go

@@ -366,11 +366,12 @@ func (c *Cluster) checkHealth(ctx context.Context) error {
 		}
 	}
 
-	// failover mons running on host path to use persistent volumes if VolumeClaimTemplate is set and vice versa
+	// failover any mons present in the mon fail over list
 	for _, mon := range c.ClusterInfo.Monitors {
-		if c.HasMonPathChanged(mon.Name) {
-			logger.Infof("fail over mon %q due to change in mon path", mon.Name)
+		if c.monsToFailover.Has(mon.Name) {
+			logger.Infof("fail over mon %q from the mon fail over list", mon.Name)
 			c.failMon(len(c.ClusterInfo.Monitors), desiredMonCount, mon.Name)
+			c.monsToFailover.Delete(mon.Name)
 			return nil
 		}
 	}
@@ -378,20 +379,6 @@ func (c *Cluster) checkHealth(ctx context.Context) error {
 	return nil
 }
 
-// HasMonPathChanged checks if the mon storage path has changed from host path to persistent volume or vice versa
-func (c *Cluster) HasMonPathChanged(mon string) bool {
-	var monPathChanged bool
-	if c.mapping.Schedule[mon] != nil && c.spec.Mon.VolumeClaimTemplate != nil {
-		logger.Infof("mon %q path has changed from host path to persistent volumes", mon)
-		monPathChanged = true
-	} else if c.mapping.Schedule[mon] == nil && c.spec.Mon.VolumeClaimTemplate == nil {
-		logger.Infof("mon %q path has changed from persistent volumes to host path", mon)
-		monPathChanged = true
-	}
-
-	return monPathChanged
-}
-
 func (c *Cluster) trackMonInOrOutOfQuorum(monName string, inQuorum bool) (bool, error) {
 	updateNeeded := false
 	var monsOutOfQuorum []string

pkg/operator/ceph/cluster/mon/health_test.go

@@ -645,37 +645,3 @@ func TestUpdateMonInterval(t *testing.T) {
 		assert.Equal(t, time.Minute, h.interval)
 	})
 }
-
-func TestHasMonPathChanged(t *testing.T) {
-	t.Run("mon path changed from pv to hostpath", func(t *testing.T) {
-		c := New(context.TODO(), &clusterd.Context{}, "ns", cephv1.ClusterSpec{}, nil)
-		c.mapping.Schedule["a"] = nil
-		result := c.HasMonPathChanged("a")
-		assert.True(t, result)
-	})
-
-	t.Run("mon path has not changed from pv to hostpath", func(t *testing.T) {
-		c := New(context.TODO(), &clusterd.Context{}, "ns", cephv1.ClusterSpec{}, nil)
-		c.spec.Mon.VolumeClaimTemplate = &v1.PersistentVolumeClaim{Spec: v1.PersistentVolumeClaimSpec{}}
-		c.mapping.Schedule["b"] = nil
-		result := c.HasMonPathChanged("b")
-		c.spec.Mon.VolumeClaimTemplate = nil
-		assert.False(t, result)
-	})
-
-	t.Run("mon path changed from hostpath to pv", func(t *testing.T) {
-		c := New(context.TODO(), &clusterd.Context{}, "ns", cephv1.ClusterSpec{}, nil)
-		c.mapping.Schedule["c"] = &opcontroller.MonScheduleInfo{}
-		c.spec.Mon.VolumeClaimTemplate = &v1.PersistentVolumeClaim{Spec: v1.PersistentVolumeClaimSpec{}}
-		result := c.HasMonPathChanged("c")
-		assert.True(t, result)
-	})
-
-	t.Run("mon path has not changed from host path to pv", func(t *testing.T) {
-		c := New(context.TODO(), &clusterd.Context{}, "ns", cephv1.ClusterSpec{}, nil)
-		c.mapping.Schedule["d"] = &opcontroller.MonScheduleInfo{}
-		result := c.HasMonPathChanged("d")
-		c.spec.Mon.VolumeClaimTemplate = nil
-		assert.False(t, result)
-	})
-}

pkg/operator/ceph/cluster/mon/mon.go

@@ -115,6 +115,8 @@ type Cluster struct {
 	ownerInfo          *k8sutil.OwnerInfo
 	isUpgrade          bool
 	arbiterMon         string
+	// list of mons to be failed over
+	monsToFailover sets.Set[string]
 }
 
 // monConfig for a single monitor
@@ -162,6 +164,7 @@ func New(ctx context.Context, clusterdContext *clusterd.Context, namespace strin
 		ClusterInfo: &cephclient.ClusterInfo{
 			Context: ctx,
 		},
+		monsToFailover: sets.New[string](),
 	}
 }
 
@@ -1230,11 +1233,6 @@ var updateDeploymentAndWait = UpdateCephDeploymentAndWait
 
 func (c *Cluster) updateMon(m *monConfig, d *apps.Deployment) error {
 
-	if c.HasMonPathChanged(m.DaemonName) {
-		logger.Infof("path has changed for mon %q. Skip updating mon deployment %q in order to failover the mon", m.DaemonName, d.Name)
-		return nil
-	}
-
 	// Expand mon PVC if storage request for mon has increased in cephcluster crd
 	if c.monVolumeClaimTemplate(m) != nil {
 		desiredPvc, err := c.makeDeploymentPVC(m, false)
@@ -1339,6 +1337,12 @@ func (c *Cluster) startMon(m *monConfig, schedule *controller.MonScheduleInfo) e
 
 	p.ApplyToPodSpec(&d.Spec.Template.Spec)
 	if deploymentExists {
+		// skip update if mon path has changed
+		if hasMonPathChanged(existingDeployment, c.spec.Mon.VolumeClaimTemplate) {
+			c.monsToFailover.Insert(m.DaemonName)
+			return nil
+		}
+
 		// the existing deployment may have a node selector. if the cluster
 		// isn't using host networking and the deployment is using pvc storage,
 		// then the node selector can be removed. this may happen after
@@ -1404,6 +1408,18 @@ func (c *Cluster) startMon(m *monConfig, schedule *controller.MonScheduleInfo) e
 	return nil
 }
 
+func hasMonPathChanged(d *apps.Deployment, claim *v1.PersistentVolumeClaim) bool {
+	if d.Labels["pvc_name"] == "" && claim != nil {
+		logger.Infof("skipping update for mon %q where path has changed from hostPath to pvc", d.Name)
+		return true
+	} else if d.Labels["pvc_name"] != "" && claim == nil {
+		logger.Infof("skipping update for mon %q where path has changed from pvc to hostPath", d.Name)
+		return true
+	}
+
+	return false
+}
+
 func waitForQuorumWithMons(context *clusterd.Context, clusterInfo *cephclient.ClusterInfo, mons []string, sleepTime int, requireAllInQuorum bool) error {
 	logger.Infof("waiting for mon quorum with %v", mons)
 

pkg/operator/ceph/cluster/mon/mon_test.go

@@ -40,6 +40,7 @@ import (
 	"github.com/rook/rook/pkg/operator/test"
 	exectest "github.com/rook/rook/pkg/util/exec/test"
 	"github.com/stretchr/testify/assert"
+	apps "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
@@ -848,3 +849,36 @@ func TestCheckIfArbiterReady(t *testing.T) {
 	assert.False(t, ready)
 	assert.Error(t, err)
 }
+
+func TestHasMonPathChanged(t *testing.T) {
+	monDeployment := &apps.Deployment{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "rook-ceph-mon-a",
+			Namespace: "test",
+			Labels: map[string]string{
+				"pvc_name": "test-pvc",
+			},
+		}}
+
+	pvcTemplate := &v1.PersistentVolumeClaim{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "test-claim",
+		},
+	}
+	t.Run("mon path changed from pv to hostpath", func(t *testing.T) {
+		assert.True(t, hasMonPathChanged(monDeployment, nil))
+	})
+
+	t.Run("mon path not changed from pv to hostpath", func(t *testing.T) {
+		assert.False(t, hasMonPathChanged(monDeployment, pvcTemplate))
+	})
+	t.Run("mon path changed from hostPath to pvc", func(t *testing.T) {
+		delete(monDeployment.Labels, "pvc_name")
+		assert.True(t, hasMonPathChanged(monDeployment, pvcTemplate))
+	})
+
+	t.Run("mon path not changed from hostPath to pvc", func(t *testing.T) {
+		delete(monDeployment.Labels, "pvc_name")
+		assert.False(t, hasMonPathChanged(monDeployment, nil))
+	})
+}