func newNamer(kubeClient *client.Client, clusterName string) (*utils.Namer, error) { name, err := getClusterUID(kubeClient, clusterName) if err != nil { return nil, err } namer := utils.NewNamer(name) vault := storage.NewConfigMapVault(kubeClient, api.NamespaceSystem, uidConfigMapName) // Start a goroutine to poll the cluster UID config map // We don't watch because we know exactly which configmap we want and this // controller already watches 5 other resources, so it isn't worth the cost // of another connection and complexity. go wait.Forever(func() { uid, found, err := vault.Get() existing := namer.GetClusterName() if found && uid != existing { glog.Infof("Cluster uid changed from %v -> %v", existing, uid) namer.SetClusterName(uid) } else if err != nil { glog.Errorf("Failed to reconcile cluster uid %v, currently set to %v", err, existing) } }, 5*time.Second) return namer, nil }
// getClusterUID returns the cluster UID. Rules for UID generation: // If the user specifies a --cluster-uid param it overwrites everything // else, check UID config map for a previously recorded uid // else, check if there are any working Ingresses // - remember that "" is the cluster uid // else, allocate a new uid func getClusterUID(kubeClient *client.Client, name string) (string, error) { cfgVault := storage.NewConfigMapVault(kubeClient, api.NamespaceSystem, uidConfigMapName) if name != "" { glog.Infof("Using user provided cluster uid %v", name) // Don't save the uid in the vault, so users can rollback through // --cluster-uid="" return name, nil } existingUID, found, err := cfgVault.Get() if found { glog.Infof("Using saved cluster uid %q", existingUID) return existingUID, nil } else if err != nil { // This can fail because of: // 1. No such config map - found=false, err=nil // 2. No such key in config map - found=false, err=nil // 3. Apiserver flake - found=false, err!=nil // It is not safe to proceed in 3. return "", fmt.Errorf("Failed to retrieve current uid: %v, using %q as name", err, name) } // Check if the cluster has an Ingress with ip ings, err := kubeClient.Extensions().Ingress(api.NamespaceAll).List(api.ListOptions{LabelSelector: labels.Everything()}) if err != nil { return "", err } namer := utils.Namer{} for _, ing := range ings.Items { if len(ing.Status.LoadBalancer.Ingress) != 0 { c := namer.ParseName(loadbalancers.GCEResourceName(ing.Annotations, "forwarding-rule")) if c.ClusterName != "" { return c.ClusterName, cfgVault.Put(c.ClusterName) } glog.Infof("Found a working Ingress, assuming uid is empty string") return "", cfgVault.Put("") } } // Allocate new uid f, err := os.Open("/dev/urandom") if err != nil { return "", err } defer f.Close() b := make([]byte, 8) if _, err := f.Read(b); err != nil { return "", err } uid := fmt.Sprintf("%x", b) return uid, cfgVault.Put(uid) }