Allow to configure delay before controller exits (#8143)

* Allow to configure delay before controller exits

Signed-off-by: Aditya Kamath <theunrealgeek@gmail.com>

* Address comments

Signed-off-by: Aditya Kamath <theunrealgeek@gmail.com>

cmd/nginx/flags.go

@@ -197,6 +197,8 @@ Takes the form "<host>:port". If not provided, no admission controller is starte
 		statusUpdateInterval = flags.Int("status-update-interval", status.UpdateInterval, "Time interval in seconds in which the status should check if an update is required. Default is 60 seconds")
 
 		shutdownGracePeriod = flags.Int("shutdown-grace-period", 0, "Seconds to wait after receiving the shutdown signal, before stopping the nginx process.")
+
+		postShutdownGracePeriod = flags.Int("post-shutdown-grace-period", 10, "Seconds to wait after the nginx process has stopped before controller exits.")
 	)
 
 	flags.StringVar(&nginx.MaxmindMirror, "maxmind-mirror", "", `Maxmind mirror url (example: http://geoip.local/databases`)
@@ -321,6 +323,7 @@ https://blog.maxmind.com/2019/12/18/significant-changes-to-accessing-and-using-g
 		PublishStatusAddress:       *publishStatusAddress,
 		UpdateStatusOnShutdown:     *updateStatusOnShutdown,
 		ShutdownGracePeriod:        *shutdownGracePeriod,
+		PostShutdownGracePeriod:    *postShutdownGracePeriod,
 		UseNodeInternalIP:          *useNodeInternalIP,
 		SyncRateLimit:              *syncRateLimit,
 		HealthCheckHost:            *healthzHost,

cmd/nginx/main.go

@@ -155,14 +155,14 @@ func main() {
 	go startHTTPServer(conf.HealthCheckHost, conf.ListenPorts.Health, mux)
 	go ngx.Start()
 
-	handleSigterm(ngx, func(code int) {
+	handleSigterm(ngx, conf.PostShutdownGracePeriod, func(code int) {
 		os.Exit(code)
 	})
 }
 
 type exiter func(code int)
 
-func handleSigterm(ngx *controller.NGINXController, exit exiter) {
+func handleSigterm(ngx *controller.NGINXController, delay int, exit exiter) {
 	signalChan := make(chan os.Signal, 1)
 	signal.Notify(signalChan, syscall.SIGTERM)
 	<-signalChan
@@ -174,8 +174,8 @@ func handleSigterm(ngx *controller.NGINXController, exit exiter) {
 		exitCode = 1
 	}
 
-	klog.InfoS("Handled quit, awaiting Pod deletion")
-	time.Sleep(10 * time.Second)
+	klog.Infof("Handled quit, delaying controller exit for %d seconds", delay)
+	time.Sleep(time.Duration(delay) * time.Second)
 
 	klog.InfoS("Exiting", "code", exitCode)
 	exit(exitCode)

cmd/nginx/main_test.go

@@ -105,7 +105,7 @@ func TestHandleSigterm(t *testing.T) {
 
 	ngx := controller.NewNGINXController(conf, nil)
 
-	go handleSigterm(ngx, func(code int) {
+	go handleSigterm(ngx, 10, func(code int) {
 		if code != 1 {
 			t.Errorf("Expected exit code 1 but %d received", code)
 		}

docs/user-guide/cli-arguments.md

@@ -40,6 +40,7 @@ They are set in the container spec of the `ingress-nginx-controller` Deployment
 | `--maxmind-retries-count`          | Number of attempts to download the GeoIP DB. (default 1) |
 | `--maxmind-license-key`            | Maxmind license key to download GeoLite2 Databases. https://blog.maxmind.com/2019/12/18/significant-changes-to-accessing-and-using-geolite2-databases |
 | `--metrics-per-host`               | Export metrics per-host (default true) |
+| `--post-shutdown-grace-period`     | Additional delay in seconds before controller container exits. (default 10) |
 | `--profiler-port`                  | Port to use for expose the ingress controller Go profiler when it is enabled. (default 10245) |
 | `--profiling`                      | Enable profiling via web interface host:port/debug/pprof/ (default true) |
 | `--publish-service`                | Service fronting the Ingress controller. Takes the form "namespace/name". When used together with update-status, the controller mirrors the address of this service's endpoints to the load-balancer status of all Ingress objects it satisfies. |

internal/ingress/controller/controller.go

@@ -118,6 +118,7 @@ type Configuration struct {
 
 	MonitorMaxBatchSize int
 
+	PostShutdownGracePeriod int
 	ShutdownGracePeriod     int
 }