feat(cli): add check for link version (#13376)

We add a linkerd.io/created-by annotation to Link resources which specifies the version of the CLI which was used to create the Link. This annotation is already used in this way by control plane components. This allows us to easily see what version of Linkerd was used to generated a Link. We add a check that inspects this value and warns if any Links don't match the current version of the CLI.

Additionally, we fix an issue with the orphaned services check where it was incorrectly warning that federated services were orphaned because they don't have a specific target cluster.

Signed-off-by: Alex Leong <[email protected]>

multicluster/cmd/check.go

@@ -176,6 +176,11 @@ func multiclusterCategory(hc *healthChecker, wait time.Duration) *healthcheck.Ca
 			WithHintAnchor("l5d-multicluster-links-are-valid").
 			Fatal().
 			WithCheck(func(ctx context.Context) error { return hc.checkLinks(ctx) }))
+	checkers = append(checkers,
+		*healthcheck.NewChecker("Link and CLI versions match").
+			WithHintAnchor("l5d-multicluster-links-version").
+			Warning().
+			WithCheck(func(ctx context.Context) error { return hc.checkLinkVersions() }))
 	checkers = append(checkers,
 		*healthcheck.NewChecker("remote cluster access credentials are valid").
 			WithHintAnchor("l5d-smc-target-clusters-access").
@@ -332,6 +337,30 @@ func (hc *healthChecker) checkLinks(ctx context.Context) error {
 	return healthcheck.VerboseSuccess{Message: strings.Join(linkNames, "\n")}
 }
 
+func (hc *healthChecker) checkLinkVersions() error {
+	errors := []error{}
+	links := []string{}
+	for _, link := range hc.links {
+		parts := strings.Split(link.CreatedBy, " ")
+		if len(parts) == 2 && parts[0] == "linkerd/cli" {
+			if parts[1] == version.Version {
+				links = append(links, fmt.Sprintf("\t* %s", link.TargetClusterName))
+			} else {
+				errors = append(errors, fmt.Errorf("* %s: CLI version is %s but Link version is %s", link.TargetClusterName, version.Version, parts[1]))
+			}
+		} else {
+			errors = append(errors, fmt.Errorf("* %s: unable to determine version", link.TargetClusterName))
+		}
+	}
+	if len(errors) > 0 {
+		return joinErrors(errors, 2)
+	}
+	if len(links) == 0 {
+		return healthcheck.SkipError{Reason: "no links"}
+	}
+	return healthcheck.VerboseSuccess{Message: strings.Join(links, "\n")}
+}
+
 func (hc *healthChecker) checkRemoteClusterConnectivity(ctx context.Context) error {
 	errors := []error{}
 	links := []string{}
@@ -668,7 +697,7 @@ func (hc *healthChecker) checkIfMirrorServicesHaveEndpoints(ctx context.Context)
 
 func (hc *healthChecker) checkForOrphanedServices(ctx context.Context) error {
 	errors := []error{}
-	selector := fmt.Sprintf("%s, !%s", k8s.MirroredResourceLabel, k8s.MirroredGatewayLabel)
+	selector := fmt.Sprintf("%s, !%s, %s", k8s.MirroredResourceLabel, k8s.MirroredGatewayLabel, k8s.RemoteClusterNameLabel)
 	mirrorServices, err := hc.KubeAPIClient().CoreV1().Services(metav1.NamespaceAll).List(ctx, metav1.ListOptions{LabelSelector: selector})
 	if err != nil {
 		return err

pkg/multicluster/link.go

@@ -39,6 +39,7 @@ type (
 	Link struct {
 		Name                          string
 		Namespace                     string
+		CreatedBy                     string
 		TargetClusterName             string
 		TargetClusterDomain           string
 		TargetClusterLinkerdNamespace string
@@ -177,6 +178,7 @@ func NewLink(u unstructured.Unstructured) (Link, error) {
 	return Link{
 		Name:                          u.GetName(),
 		Namespace:                     u.GetNamespace(),
+		CreatedBy:                     u.GetAnnotations()[k8s.CreatedByAnnotation],
 		TargetClusterName:             targetClusterName,
 		TargetClusterDomain:           targetClusterDomain,
 		TargetClusterLinkerdNamespace: targetClusterLinkerdNamespace,
@@ -260,6 +262,9 @@ func (l Link) ToUnstructured() (unstructured.Unstructured, error) {
 			"metadata": map[string]interface{}{
 				"name":      l.Name,
 				"namespace": l.Namespace,
+				"annotations": map[string]string{
+					k8s.CreatedByAnnotation: k8s.CreatedByAnnotationValue(),
+				},
 			},
 			"spec":   spec,
 			"status": map[string]interface{}{},