util: add support to configure mirror daemon count

Currently we are assuming that only one
rbd mirror daemon running on the ceph cluster
but that is not true for many cases and it
can be more that one, this PR make this as a
configurable parameter.

fixes: ceph#4312

Signed-off-by: Madhu Rajanna <[email protected]>

charts/ceph-csi-rbd/values.yaml

@@ -27,6 +27,7 @@ serviceAccounts:
 #       - "<MONValue2>"
 #     rbd:
 #       netNamespaceFilePath: "{{ .kubeletDir }}/plugins/{{ .driverName }}/net"
+#       mirrorDaemonCount: 1
 #     readAffinity:
 #       enabled: true
 #       crushLocationLabels:

deploy/csi-config-map-sample.yaml

@@ -19,6 +19,8 @@ kind: ConfigMap
 # NOTE: The given radosNamespace must already exists in the pool.
 # NOTE: Make sure you don't add radosNamespace option to a currently in use
 # configuration as it will cause issues.
+# The "rbd.mirrorDaemonCount" is optional and represents the total number of
+# RBD mirror daemons running on the ceph cluster.
 # The field "cephFS.subvolumeGroup" is optional and defaults to "csi".
 # NOTE: The given subvolumeGroup must already exist in the filesystem.
 # The "cephFS.netNamespaceFilePath" fields are the various network namespace
@@ -64,6 +66,7 @@ data:
         "rbd": {
            "netNamespaceFilePath": "<kubeletRootPath>/plugins/rbd.csi.ceph.com/net",
            "radosNamespace": "<rados-namespace>",
+           "mirrorDaemonCount": 1,
         },
         "monitors": [
           "<MONValue1>",

internal/rbd/rbd_util.go

@@ -553,9 +553,13 @@ func (ri *rbdImage) isInUse() (bool, error) {
 	// because we opened the image, there is at least one watcher
 	defaultWatchers := 1
 	if mirrorInfo.Primary {
+		count, err := util.GetRBDMirrorDaemonCount(util.CsiConfigFile, ri.ClusterID)
+		if err != nil {
+			return false, err
+		}
 		// if rbd mirror daemon is running, a watcher will be added by the rbd
 		// mirror daemon for mirrored images.
-		defaultWatchers++
+		defaultWatchers += count
 	}
 
 	return len(watchers) > defaultWatchers, nil

internal/util/csiconfig.go

@@ -45,6 +45,7 @@ const (
 	"clusterID": "<cluster-id>",
 	"rbd": {
 		"radosNamespace": "<rados-namespace>"
+		"mirrorDaemonCount": 1
 	},
 	"monitors": [
 		"<monitor-value>",
@@ -105,6 +106,22 @@ func GetRadosNamespace(pathToConfig, clusterID string) (string, error) {
 	return cluster.RBD.RadosNamespace, nil
 }
 
+// GetRBDMirrorDaemonCount returns the number of mirror daemon count for the
+// given clusterID.
+func GetRBDMirrorDaemonCount(pathToConfig, clusterID string) (int, error) {
+	cluster, err := readClusterInfo(pathToConfig, clusterID)
+	if err != nil {
+		return 0, err
+	}
+
+	// if it is empty, set the default to 1 which is most common in a cluster.
+	if cluster.RBD.MirrorDaemonCount == 0 {
+		return 1, nil
+	}
+
+	return cluster.RBD.MirrorDaemonCount, nil
+}
+
 // CephFSSubvolumeGroup returns the subvolumeGroup for CephFS volumes. If not set, it returns the default value "csi".
 func CephFSSubvolumeGroup(pathToConfig, clusterID string) (string, error) {
 	cluster, err := readClusterInfo(pathToConfig, clusterID)

internal/util/csiconfig_test.go

@@ -17,11 +17,14 @@ limitations under the License.
 package util
 
 import (
+	"bytes"
 	"encoding/json"
 	"os"
 	"testing"
 
 	cephcsi "github.com/ceph/ceph-csi/api/deploy/kubernetes"
+
+	"github.com/stretchr/testify/require"
 )
 
 var (
@@ -530,3 +533,88 @@ func TestGetCephFSMountOptions(t *testing.T) {
 		})
 	}
 }
+
+func TestGetRBDMirrorDaemonCount(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name      string
+		clusterID string
+		want      int
+	}{
+		{
+			name:      "get rbd mirror daemon count for cluster-1",
+			clusterID: "cluster-1",
+			want:      2,
+		},
+		{
+			name:      "get rbd mirror daemon count for cluster-2",
+			clusterID: "cluster-2",
+			want:      4,
+		},
+		{
+			name:      "when rbd mirror daemon count is empty",
+			clusterID: "cluster-3",
+			want:      1, // default mirror daemon count
+		},
+	}
+
+	csiConfig := []cephcsi.ClusterInfo{
+		{
+			ClusterID: "cluster-1",
+			Monitors:  []string{"ip-1", "ip-2"},
+			RBD: cephcsi.RBD{
+				MirrorDaemonCount: 2,
+			},
+		},
+		{
+			ClusterID: "cluster-2",
+			Monitors:  []string{"ip-3", "ip-4"},
+			RBD: cephcsi.RBD{
+				MirrorDaemonCount: 4,
+			},
+		},
+		{
+			ClusterID: "cluster-3",
+			Monitors:  []string{"ip-5", "ip-6"},
+		},
+	}
+	csiConfigFileContent, err := json.Marshal(csiConfig)
+	if err != nil {
+		t.Errorf("failed to marshal csi config info %v", err)
+	}
+	tmpConfPath := t.TempDir() + "/ceph-csi.json"
+	err = os.WriteFile(tmpConfPath, csiConfigFileContent, 0o600)
+	if err != nil {
+		t.Errorf("failed to write %s file content: %v", CsiConfigFile, err)
+	}
+	for _, tt := range tests {
+		ts := tt
+		t.Run(ts.name, func(t *testing.T) {
+			t.Parallel()
+			var got int
+			got, err = GetRBDMirrorDaemonCount(tmpConfPath, ts.clusterID)
+			if err != nil {
+				t.Errorf("GetRBDMirrorDaemonCount() error = %v", err)
+
+				return
+			}
+			if got != ts.want {
+				t.Errorf("GetRBDMirrorDaemonCount() = %v, want %v", got, ts.want)
+			}
+		})
+	}
+
+	// when mirrorDaemonCount is set as string
+	csiConfigFileContent = bytes.Replace(
+		csiConfigFileContent,
+		[]byte(`"mirrorDaemonCount":2`),
+		[]byte(`"mirrorDaemonCount":"2"`),
+		1)
+	tmpCSIConfPath := t.TempDir() + "/ceph-csi.json"
+	err = os.WriteFile(tmpCSIConfPath, csiConfigFileContent, 0o600)
+	if err != nil {
+		t.Errorf("failed to write %s file content: %v", CsiConfigFile, err)
+	}
+	_, err = GetRBDMirrorDaemonCount(tmpCSIConfPath, "test")
+	require.Error(t, err)
+}