Add capability to watch multiple namespaces

README.md

@@ -55,6 +55,8 @@ original Secret from the SealedSecret.
   - [Can I bring my own (pre-generated) certificates?](#can-i-bring-my-own-pre-generated-certificates)
   - [How to use kubeseal if the controller is not running within the `kube-system` namespace?](#how-to-use-kubeseal-if-the-controller-is-not-running-within-the-kube-system-namespace)
   - [How to verify the images?](#how-to-verify-the-images)
+  - [How to use one controller for a subset of namespaces](#How-to-use-one-controller-for-a-subset-of-namespaces)
+
 - [Community](#community)
   - [Related projects](#related-projects)
 
@@ -648,6 +650,10 @@ cosign verify --key .github/workflows/cosign.pub ghcr.io/bitnami-labs/sealed-sec
 cosign verify --key .github/workflows/cosign.pub docker.io/bitnami/sealed-secrets-controller:latest
 ```
 
+### How to use one controller for a subset of namespaces
+
+If you want to use one controller for more than one namespace, but not all namespaces, you can provide additional namespaces using the command line flag `--additional-namespaces=<namespace1>,<namespace2>,<...>`. Make sure you provide appropriate roles and rolebindings in the target namespaces, so the controller can manage the secrets in there.
+
 ## Community
 
 - [#sealed-secrets on Kubernetes Slack](https://kubernetes.slack.com/messages/sealed-secrets)

cmd/controller/funcs.go

@@ -45,3 +45,15 @@ func validateKeyPrefix(name string) (string, error) {
 	}
 	return name, nil
 }
+
+func removeDuplicates(strSlice []string) []string {
+	allKeys := make(map[string]bool)
+	list := []string{}
+	for _, item := range strSlice {
+		if _, value := allKeys[item]; !value {
+			allKeys[item] = true
+			list = append(list, item)
+		}
+	}
+	return list
+}

cmd/controller/main.go

@@ -39,16 +39,17 @@ const (
 )
 
 var (
-	keyPrefix      = flag.String("key-prefix", "sealed-secrets-key", "Prefix used to name keys.")
-	keySize        = flag.Int("key-size", 4096, "Size of encryption key.")
-	validFor       = flag.Duration("key-ttl", 10*365*24*time.Hour, "Duration that certificate is valid for.")
-	myCN           = flag.String("my-cn", "", "Common name to be used as issuer/subject DN in generated certificate.")
-	printVersion   = flag.Bool("version", false, "Print version information and exit")
-	keyRenewPeriod = flag.Duration("key-renew-period", defaultKeyRenewPeriod, "New key generation period (automatic rotation disabled if 0)")
-	acceptV1Data   = flag.Bool("accept-deprecated-v1-data", true, "Accept deprecated V1 data field.")
-	keyCutoffTime  = flag.String("key-cutoff-time", "", "Create a new key if latest one is older than this cutoff time. RFC1123 format with numeric timezone expected.")
-	namespaceAll   = flag.Bool("all-namespaces", true, "Scan all namespaces or only the current namespace (default=true).")
-	labelSelector  = flag.String("label-selector", "", "Label selector which can be used to filter sealed secrets.")
+	keyPrefix            = flag.String("key-prefix", "sealed-secrets-key", "Prefix used to name keys.")
+	keySize              = flag.Int("key-size", 4096, "Size of encryption key.")
+	validFor             = flag.Duration("key-ttl", 10*365*24*time.Hour, "Duration that certificate is valid for.")
+	myCN                 = flag.String("my-cn", "", "Common name to be used as issuer/subject DN in generated certificate.")
+	printVersion         = flag.Bool("version", false, "Print version information and exit")
+	keyRenewPeriod       = flag.Duration("key-renew-period", defaultKeyRenewPeriod, "New key generation period (automatic rotation disabled if 0)")
+	acceptV1Data         = flag.Bool("accept-deprecated-v1-data", true, "Accept deprecated V1 data field.")
+	keyCutoffTime        = flag.String("key-cutoff-time", "", "Create a new key if latest one is older than this cutoff time. RFC1123 format with numeric timezone expected.")
+	namespaceAll         = flag.Bool("all-namespaces", true, "Scan all namespaces or only the current namespace (default=true).")
+	additionalNamespaces = flag.String("additional-namespaces", "", "Comma-separated list of additional namespaces to be scanned.")
+	labelSelector        = flag.String("label-selector", "", "Label selector which can be used to filter sealed secrets.")
 
 	oldGCBehavior = flag.Bool("old-gc-behaviour", false, "Revert to old GC behavior where the controller deletes secrets instead of delegating that to k8s itself.")
 
@@ -210,8 +211,9 @@ func main2() error {
 	initKeyGenSignalListener(trigger)
 
 	namespace := v1.NamespaceAll
-	if !*namespaceAll {
+	if !*namespaceAll || *additionalNamespaces != "" {
 		namespace = myNamespace()
+		log.Printf("Starting informer for namespace: %s\n", namespace)
 	}
 
 	var tweakopts func(*metav1.ListOptions) = nil
@@ -231,6 +233,31 @@ func main2() error {
 
 	go controller.Run(stop)
 
+	if *additionalNamespaces != "" {
+		addNS := removeDuplicates(strings.Split(*additionalNamespaces, ","))
+
+		var inf ssinformers.SharedInformerFactory
+		var ctlr *Controller
+
+		for _, ns := range addNS {
+			if _, err := clientset.CoreV1().Namespaces().Get(ctx, ns, metav1.GetOptions{}); err != nil {
+				if errors.IsNotFound(err) {
+					log.Printf("Warning: namespace '%s' doesn't exist\n", ns)
+					continue
+				}
+				return err
+			}
+			if ns != namespace {
+				inf = ssinformers.NewFilteredSharedInformerFactory(ssclientset, 0, ns, tweakopts)
+				ctlr = NewController(clientset, ssclientset, inf, keyRegistry)
+				ctlr.oldGCBehavior = *oldGCBehavior
+				ctlr.updateStatus = *updateStatus
+				log.Printf("Starting informer for namespace: %s\n", ns)
+				go ctlr.Run(stop)
+			}
+		}
+	}
+
 	cp := func() ([]*x509.Certificate, error) {
 		cert, err := keyRegistry.getCert()
 		if err != nil {