pool: skip updating crush rules for stretch clusters

Pools in stretch clusters must all specify the same
CRUSH rule. No pools can use a different rule. When there
is a change in the device class, we do not even expect to update
the crush rules in a stretch cluster. Different device classes
are not supported in stretch clusters, and it's expected to be
a homogenous environment. Therefore, skip all crush rule updates
in stretch clusters.

Signed-off-by: Travis Nielsen <tnielsen@redhat.com>
(cherry picked from commit b92bbba)
(cherry picked from commit cde2c00)

pkg/daemon/ceph/client/pool.go

@@ -463,6 +463,11 @@ func createReplicatedPoolForApp(context *clusterd.Context, clusterInfo *ClusterI
 }
 
 func updatePoolCrushRule(context *clusterd.Context, clusterInfo *ClusterInfo, clusterSpec *cephv1.ClusterSpec, pool cephv1.NamedPoolSpec) error {
+	if clusterSpec.IsStretchCluster() {
+		logger.Debugf("skipping crush rule update for pool %q in a stretch cluster", pool.Name)
+		return nil
+	}
+
 	if pool.FailureDomain == "" && pool.DeviceClass == "" {
 		logger.Debugf("skipping check for failure domain and deviceClass on pool %q as it is not specified", pool.Name)
 		return nil

pkg/daemon/ceph/client/pool_test.go

@@ -251,10 +251,12 @@ func TestUpdateFailureDomain(t *testing.T) {
 	currentFailureDomain := "rack"
 	currentDeviceClass := "default"
 	testCrushRuleName := "test_rule"
+	cephCommandCalled := false
 	executor := &exectest.MockExecutor{}
 	context := &clusterd.Context{Executor: executor}
 	executor.MockExecuteCommandWithOutput = func(command string, args ...string) (string, error) {
 		logger.Infof("Command: %s %v", command, args)
+		cephCommandCalled = true
 		if args[1] == "pool" {
 			if args[2] == "get" {
 				assert.Equal(t, "mypool", args[3])
@@ -318,6 +320,27 @@ func TestUpdateFailureDomain(t *testing.T) {
 		assert.NoError(t, err)
 		assert.Equal(t, "mypool_zone", newCrushRule)
 	})
+
+	t.Run("stretch cluster skips crush rule update", func(t *testing.T) {
+		p := cephv1.NamedPoolSpec{
+			Name: "mypool",
+			PoolSpec: cephv1.PoolSpec{
+				FailureDomain:      "zone",
+				Replicated:         cephv1.ReplicatedSpec{Size: 3},
+				EnableCrushUpdates: true,
+			},
+		}
+		clusterSpec := &cephv1.ClusterSpec{
+			Mon:     cephv1.MonSpec{StretchCluster: &cephv1.StretchClusterSpec{Zones: []cephv1.MonZoneSpec{{Name: "zone1"}, {Name: "zone2"}, {Name: "zone3", Arbiter: true}}}},
+			Storage: cephv1.StorageScopeSpec{},
+		}
+		newCrushRule = ""
+		cephCommandCalled = false
+		err := updatePoolCrushRule(context, AdminTestClusterInfo("mycluster"), clusterSpec, p)
+		assert.NoError(t, err)
+		assert.Equal(t, "", newCrushRule)
+		assert.False(t, cephCommandCalled)
+	})
 }
 
 func TestExtractPoolDetails(t *testing.T) {