core: skip reconcile if override configmap is empty

If the configmap rook-config-override is empty,
there is no need to trigger the reconcile to update
the ceph daemons. This configmap update is causing
unnecessary reconciles periodically in some clusters
even when it is empty.

Signed-off-by: travisn <tnielsen@redhat.com>

pkg/operator/ceph/controller/predicate.go

@@ -579,11 +579,14 @@ func WatchPredicateForNonCRDObject(owner runtime.Object, scheme *runtime.Scheme)
 				logger.Debugf("object %q matched on update", objectName)
 
 				// CONFIGMAP WHITELIST
-				// Only reconcile on rook-config-override CM changes
-				isCMTConfigOverride := isCMTConfigOverride(e.ObjectNew)
+				// Only reconcile on rook-config-override CM changes if the configmap is not empty
+				isCMTConfigOverride, configmapIsEmpty := isCMTConfigOverride(e.ObjectNew)
 				if isCMTConfigOverride {
-					logger.Debugf("do reconcile when the cm is %s", k8sutil.ConfigOverrideName)
-					return true
+					if !configmapIsEmpty {
+						logger.Infof("reconcile due to updated configmap %s", k8sutil.ConfigOverrideName)
+						return true
+					}
+					logger.Infof("do not reconcile since configmap %s config is empty", k8sutil.ConfigOverrideName)
 				}
 
 				// If the resource is a ConfigMap we don't reconcile
@@ -747,15 +750,23 @@ func isDeployment(obj runtime.Object, appName string) bool {
 	return false
 }
 
-func isCMTConfigOverride(obj runtime.Object) bool {
+func isCMTConfigOverride(obj runtime.Object) (bool, bool) {
 	// If not a ConfigMap, let's not reconcile
 	cm, ok := obj.(*corev1.ConfigMap)
 	if !ok {
-		return false
+		return false, false
 	}
 
 	objectName := cm.GetName()
-	return objectName == k8sutil.ConfigOverrideName
+	shouldReconcile := false
+	isEmpty := len(cm.Data) == 0
+	if objectName == k8sutil.ConfigOverrideName {
+		shouldReconcile = true
+		if cm.Data[k8sutil.ConfigOverrideVal] == "" {
+			isEmpty = true
+		}
+	}
+	return shouldReconcile, isEmpty
 }
 
 func isCMToIgnoreOnDelete(obj runtime.Object) bool {

pkg/operator/ceph/controller/predicate_test.go

@@ -164,16 +164,39 @@ func TestIsCanary(t *testing.T) {
 
 func TestIsCMToIgnoreOnUpdate(t *testing.T) {
 	blockPool := &cephv1.CephBlockPool{}
-	assert.False(t, isCMTConfigOverride(blockPool))
+	reconcile, isEmpty := isCMTConfigOverride(blockPool)
+	assert.False(t, reconcile)
+	assert.False(t, isEmpty)
 
 	cm := &corev1.ConfigMap{}
-	assert.False(t, isCMTConfigOverride(cm))
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.False(t, reconcile)
+	assert.True(t, isEmpty)
 
 	cm.Name = "rook-ceph-mon-endpoints"
-	assert.False(t, isCMTConfigOverride(cm))
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.False(t, reconcile)
+	assert.True(t, isEmpty)
 
 	cm.Name = "rook-config-override"
-	assert.True(t, isCMTConfigOverride(cm))
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.True(t, reconcile)
+	assert.True(t, isEmpty)
+
+	cm.Data = map[string]string{"foo": "bar"}
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.True(t, reconcile)
+	assert.True(t, isEmpty)
+
+	cm.Data = map[string]string{"config": ""}
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.True(t, reconcile)
+	assert.True(t, isEmpty)
+
+	cm.Data = map[string]string{"config": "somevalue"}
+	reconcile, isEmpty = isCMTConfigOverride(cm)
+	assert.True(t, reconcile)
+	assert.False(t, isEmpty)
 }
 
 func TestIsCMToIgnoreOnDelete(t *testing.T) {