Merge pull request #125 from verult/http-endpoint

Introduce http-endpoint flag

README.md

@@ -52,9 +52,13 @@ There are two UNIX domain sockets used by the node-driver-registrar:
 
 ### Optional arguments
 
-* `--health-port`: This is the port of the health check server for the node-driver-registrar,
-  which checks if the registration socket exists. A value <= 0 disables the server.
-  Server is disabled by default.
+* `--http-endpoint`: "The TCP network address where the HTTP server for diagnostics, including
+  the health check indicating whether the registration socket exists, will listen (example:
+  `:8080`). The default is empty string, which means the server is disabled.
+
+* `--health-port`: (deprecated) This is the port of the health check server for the
+  node-driver-registrar, which checks if the registration socket exists. A value <= 0 disables
+  the server. Server is disabled by default.
 
 ### Required permissions
 
@@ -70,6 +74,11 @@ permissions to:
 * Access the registration socket (typically in `/var/lib/kubelet/plugins_registry/`).
   * Used by the `node-driver-registrar` to register the driver with kubelet.
 
+### Health Check
+
+If `--http-endpoint` is set, the node-driver-registrar exposes a health check endpoint at the
+specified address and the path `/healthz`, indicating whether the registration socket exists.
+
 ### Example
 
 Here is an example sidecar spec in the driver DaemonSet. `<drivername.example.com>` should be replaced by

cmd/csi-node-driver-registrar/main.go

@@ -21,6 +21,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"strconv"
 	"time"
 
 	"github.com/kubernetes-csi/csi-lib-utils/metrics"
@@ -49,7 +50,8 @@ var (
 	csiAddress              = flag.String("csi-address", "/run/csi/socket", "Path of the CSI driver socket that the node-driver-registrar will connect to.")
 	pluginRegistrationPath  = flag.String("plugin-registration-path", "/registration", "Path to Kubernetes plugin registration directory.")
 	kubeletRegistrationPath = flag.String("kubelet-registration-path", "", "Path of the CSI driver socket on the Kubernetes host machine.")
-	healthzPort             = flag.Int("health-port", 0, "TCP port for healthz requests. Set to 0 to disable the healthz server.")
+	healthzPort             = flag.Int("health-port", 0, "(deprecated) TCP port for healthz requests. Set to 0 to disable the healthz server. Only one of `--health-port` and `--http-endpoint` can be set.")
+	httpEndpoint            = flag.String("http-endpoint", "", "The TCP network address where the HTTP server for diagnostics, including the health check indicating whether the registration socket exists, will listen (example: `:8080`). The default is empty string, which means the server is disabled. Only one of `--health-port` and `--http-endpoint` can be set.")
 	showVersion             = flag.Bool("version", false, "Show version.")
 	version                 = "unknown"
 
@@ -112,6 +114,17 @@ func main() {
 	}
 	klog.Infof("Version: %s", version)
 
+	if *healthzPort > 0 && *httpEndpoint != "" {
+		klog.Error("only one of `--health-port` and `--http-endpoint` can be set.")
+		os.Exit(1)
+	}
+	var addr string
+	if *healthzPort > 0 {
+		addr = ":" + strconv.Itoa(*healthzPort)
+	} else {
+		addr = *httpEndpoint
+	}
+
 	if *connectionTimeout != 0 {
 		klog.Warning("--connection-timeout is deprecated and will have no effect")
 	}
@@ -144,5 +157,5 @@ func main() {
 	cmm.SetDriverName(csiDriverName)
 
 	// Run forever
-	nodeRegister(csiDriverName)
+	nodeRegister(csiDriverName, addr)
 }

cmd/csi-node-driver-registrar/node_register.go

@@ -23,7 +23,6 @@ import (
 	"os"
 	"os/signal"
 	"runtime"
-	"strconv"
 	"syscall"
 
 	"google.golang.org/grpc"
@@ -33,9 +32,7 @@ import (
 	registerapi "k8s.io/kubelet/pkg/apis/pluginregistration/v1"
 )
 
-func nodeRegister(
-	csiDriverName string,
-) {
+func nodeRegister(csiDriverName, httpEndpoint string) {
 	// When kubeletRegistrationPath is specified then driver-registrar ONLY acts
 	// as gRPC server which replies to registration requests initiated by kubelet's
 	// pluginswatcher infrastructure. Node labeling is done by kubelet's csi code.
@@ -66,7 +63,7 @@ func nodeRegister(
 	// Registers kubelet plugin watcher api.
 	registerapi.RegisterRegistrationServer(grpcServer, registrar)
 
-	go healthzServer(socketPath, *healthzPort)
+	go healthzServer(socketPath, httpEndpoint)
 	go removeRegSocket(csiDriverName)
 	// Starts service
 	if err := grpcServer.Serve(lis); err != nil {
@@ -81,12 +78,12 @@ func buildSocketPath(csiDriverName string) string {
 	return fmt.Sprintf("%s/%s-reg.sock", *pluginRegistrationPath, csiDriverName)
 }
 
-func healthzServer(socketPath string, port int) {
-	if port <= 0 {
-		klog.Infof("Skipping healthz server because port set to: %v", port)
+func healthzServer(socketPath string, httpEndpoint string) {
+	if httpEndpoint == "" {
+		klog.Infof("Skipping healthz server because HTTP endpoint is set to: %q", httpEndpoint)
 		return
 	}
-	klog.Infof("Starting healthz server on port: %v\n", port)
+	klog.Infof("Starting healthz server at HTTP endpoint: %v\n", httpEndpoint)
 
 	http.HandleFunc("/healthz", func(w http.ResponseWriter, req *http.Request) {
 		socketExists, err := util.DoesSocketExist(socketPath)
@@ -105,7 +102,7 @@ func healthzServer(socketPath string, port int) {
 		}
 	})
 
-	klog.Fatal(http.ListenAndServe(":"+strconv.Itoa(port), nil))
+	klog.Fatal(http.ListenAndServe(httpEndpoint, nil))
 }
 
 func removeRegSocket(csiDriverName string) {