kubectl-moco: add switchover subcommand

cmd/kubectl-moco/cmd/credential.go

@@ -14,7 +14,7 @@ var credentialConfig struct {
 
 // credentialCmd represents the credential command
 var credentialCmd = &cobra.Command{
-	Use:   "credential <CLUSTER_NAME>",
+	Use:   "credential CLUSTER_NAME",
 	Short: "Fetch the credential of a specified user",
 	Long:  "Fetch the credential of a specified user.",
 	Args:  cobra.ExactArgs(1),

cmd/kubectl-moco/cmd/mysql.go

@@ -29,7 +29,7 @@ var mysqlConfig struct {
 
 // mysqlCmd represents the mysql command
 var mysqlCmd = &cobra.Command{
-	Use:   "mysql <CLUSTER_NAME> [COMMANDS]",
+	Use:   "mysql CLUSTER_NAME -- [COMMANDS]",
 	Short: "Run mysql command in a specified MySQL instance",
 	Long:  "Run mysql command in a specified MySQL instance.",
 	Args:  cobra.MinimumNArgs(1),

cmd/kubectl-moco/cmd/switchover.go

@@ -0,0 +1,50 @@
+package cmd
+
+import (
+	"context"
+	"errors"
+
+	mocov1beta1 "github.com/cybozu-go/moco/api/v1beta1"
+	"github.com/cybozu-go/moco/pkg/constants"
+	"github.com/spf13/cobra"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
+)
+
+var switchoverCmd = &cobra.Command{
+	Use:   "switchover CLUSTER_NAME",
+	Short: "Switch the primary instance",
+	Long:  "Switch the primary instance to one of the replicas.",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return switchover(cmd.Context(), args[0])
+	},
+}
+
+func switchover(ctx context.Context, name string) error {
+	cluster := &mocov1beta1.MySQLCluster{}
+	if err := kubeClient.Get(ctx, types.NamespacedName{Namespace: namespace, Name: name}, cluster); err != nil {
+		return err
+	}
+
+	if cluster.Spec.Replicas == 1 {
+		return errors.New("single-instance cluster is not able to switch")
+	}
+
+	podName := cluster.PodName(cluster.Status.CurrentPrimaryIndex)
+	pod := &corev1.Pod{}
+	if err := kubeClient.Get(ctx, types.NamespacedName{Namespace: namespace, Name: podName}, pod); err != nil {
+		return err
+	}
+
+	if pod.Annotations == nil {
+		pod.Annotations = make(map[string]string)
+	}
+	pod.Annotations[constants.AnnDemote] = "true"
+
+	return kubeClient.Update(ctx, pod)
+}
+
+func init() {
+	rootCmd.AddCommand(switchoverCmd)
+}

docs/kubectl-moco.md

@@ -65,3 +65,7 @@ Fetch the credential information of a specified user
 | ------------------ | --------------- | ------------------------------------------ |
 | `-u, --mysql-user` | `moco-readonly` | Fetch the credential of the specified user |
 | `--format`         | `plain`         | Output format: `plain` or `mycnf`          |
+
+## `kubectl moco switchover CLUSTER_NAME`
+
+Switch the primary instance to one of the replicas.

docs/usage.md

@@ -399,11 +399,8 @@ Switchver is an operation to change the live primary to one of the replicas.
 
 MOCO automatically switch the primary when the Pod of the primary instance is to be deleted.
 
-Users can manually trigger a switchover by annotating the Pod of the primary instance with `moco.cybozu.com/demote: true`.  You can use `kubectl` to do this:
-
-```console
-$ kubectl annotate mysqlcluster <name> moco.cybozu.com/demote=true
-```
+Users can manually trigger a switchover with `kubectl moco switchover CLUSTER_NAME`.
+Read [`kubectl-moco.md`](kubectl-moco.md) for details.
 
 ### Failover
 

e2e/replication_test.go

@@ -114,7 +114,7 @@ var _ = Context("replication", func() {
 	})
 
 	It("should switch the primary if requested", func() {
-		kubectlSafe(nil, "-n", "repl", "annotate", "pod", "moco-test-0", "moco.cybozu.com/demote=true")
+		kubectlSafe(nil, "moco", "-n", "repl", "switchover", "test")
 		Eventually(func() int {
 			cluster, err := getCluster("repl", "test")
 			if err != nil {

e2e/upgrade_test.go

@@ -70,7 +70,7 @@ var _ = Context("upgrade", func() {
 		fmt.Printf("The current primary = %d\n", primary)
 
 		By("doing a switchover")
-		kubectlSafe(nil, "annotate", "-n", "upgrade", "pod", cluster.PodName(primary), "moco.cybozu.com/demote=true")
+		kubectlSafe(nil, "moco", "-n", "upgrade", "switchover", "test")
 		Eventually(func() error {
 			var err error
 			cluster, err = getCluster("upgrade", "test")