diff --git a/controllers/gce/examples/websocket/Dockerfile b/controllers/gce/examples/websocket/Dockerfile new file mode 100644 index 000000000..b5e679af2 --- /dev/null +++ b/controllers/gce/examples/websocket/Dockerfile @@ -0,0 +1,5 @@ +FROM alpine:3.5 + +COPY wsserver /wsserver + +CMD ["/wsserver"] diff --git a/controllers/gce/examples/websocket/README.md b/controllers/gce/examples/websocket/README.md new file mode 100644 index 000000000..b2fe8657f --- /dev/null +++ b/controllers/gce/examples/websocket/README.md @@ -0,0 +1,109 @@ +# Simple Websocket Example + +Any websocket server will suffice; however, for the purpose of demonstration, we'll use the gorilla/websocket package in a Go process. + +### Build +```shell +➜ CGO_ENABLED=0 go build -o wsserver +``` + +### Containerize +```shell +➜ docker build -t nicksardo/websocketexample . +Sending build context to Docker daemon 6.134 MB +Step 1 : FROM alpine:3.5 + ---> 4a415e366388 +Step 2 : COPY wsserver /wsserver + ---> 8002887d752d +Removing intermediate container 7772a3e76155 +Step 3 : CMD /wsserver + ---> Running in 27c8ff226267 + ---> eecd0574e5d1 +Removing intermediate container 27c8ff226267 +Successfully built eecd0574e5d1 + +➜ docker push nicksardo/websocketexample:latest +... +``` + +### Deploy +Either update the image in the `Deployment` to your newly created image or continue using `nicksardo/websocketexample.` +```shell +➜ vi deployment.yaml +# Change image to your own +``` + +```shell +➜ kubectl create -f deployment.yaml +deployment "ws-example" created +service "ws-example-svc" created +ingress "ws-example-ing" created + +``` + +### Test +Retrieve the ingress external IP: +```shell +➜ kubectl get ing/ws-example-ing +NAME HOSTS ADDRESS PORTS AGE +ws-example-ing * xxx.xxx.xxx.xxx 80 3m +``` + +Wait for the loadbalancer to be created and functioning. When you receive a successful response, you can proceed. +``` +➜ curl http://xxx.xxx.xxx.xxx +Websocket example. Connect to /ws% +``` + +The binary we deployed does not have any html/javascript to demonstrate thwe websocket, so we'll use websocket.org's client. + +Visit http://www.websocket.org/echo.html. It's important to use `HTTP` instead of `HTTPS` since we assembled an `HTTP` load balancer. Browsers may prevent `HTTP` websocket connections as a security feature. +Set the `Location` to +``` +ws://xxx.xxx.xxx.xxx/ws +``` +Click 'Connect' and you should see messages received from server: +![Log screenshot](http://i.imgur.com/hlwwa0G.png) + + +### Change backend timeout + +At this point, the websocket connection will be destroyed by the HTTP(S) Load Balancer after 30 seconds, which is the default timeout. Note: this timeout is not an idle timeout - it's a timeout on the connection lifetime. + +Currently, the GCE ingress controller does not provide a way to set this timeout via Ingress specification. You'll need to change this value either through the GCP Cloud Console or through gcloud CLI. + + +```shell +➜ kubectl describe ingress/ws-example-ing +Name: ws-example-ing +Namespace: default +Address: xxxxxxxxxxxx +Default backend: ws-example-svc:80 (10.48.10.12:8080,10.48.5.14:8080,10.48.7.11:8080) +Rules: + Host Path Backends + ---- ---- -------- + * * ws-example-svc:80 (10.48.10.12:8080,10.48.5.14:8080,10.48.7.11:8080) +Annotations: + target-proxy: k8s-tp-default-ws-example-ing--52aa8ae8221ffa9c + url-map: k8s-um-default-ws-example-ing--52aa8ae8221ffa9c + backends: {"k8s-be-31127--52aa8ae8221ffa9c":"HEALTHY"} + forwarding-rule: k8s-fw-default-ws-example-ing--52aa8ae8221ffa9c +Events: + FirstSeen LastSeen Count From SubObjectPath Type Reason Message + --------- -------- ----- ---- ------------- -------- ------ ------- + 12m 12m 1 loadbalancer-controller Normal ADD default/ws-example-ing + 11m 11m 1 loadbalancer-controller Normal CREATE ip: xxxxxxxxxxxx + 11m 9m 5 loadbalancer-controller Normal Service default backend set to ws-example-svc:31127 +``` + +Retrieve the name of the backend service from within the annotation section. + +Update the timeout field for every backend that needs a higher timeout. + +```shell +➜ export BACKEND=k8s-be-31127--52aa8ae8221ffa9c +➜ gcloud compute backend-services update $BACKEND --global --timeout=86400 # seconds +Updated [https://www.googleapis.com/compute/v1/projects/xxxxxxxxx/global/backendServices/k8s-be-31127--52aa8ae8221ffa9c]. +``` + +Wait up to twenty minutes for this change to propagate. diff --git a/controllers/gce/examples/websocket/deployment.yaml b/controllers/gce/examples/websocket/deployment.yaml new file mode 100644 index 000000000..e9c9d3917 --- /dev/null +++ b/controllers/gce/examples/websocket/deployment.yaml @@ -0,0 +1,47 @@ +apiVersion: extensions/v1beta1 +kind: Deployment +metadata: + name: ws-example +spec: + replicas: 3 + template: + metadata: + labels: + app: wseg + spec: + containers: + - name: websocketexample + image: nicksardo/websocketexample + imagePullPolicy: Always + ports: + - name: http + containerPort: 8080 + env: + - name: podname + valueFrom: + fieldRef: + fieldPath: metadata.name +--- +apiVersion: v1 +kind: Service +metadata: + name: ws-example-svc + labels: + app: wseg +spec: + type: NodePort + ports: + - port: 80 + targetPort: 8080 + protocol: TCP + selector: + app: wseg +--- +apiVersion: extensions/v1beta1 +kind: Ingress +metadata: + name: ws-example-ing +spec: + backend: + serviceName: ws-example-svc + servicePort: 80 diff --git a/controllers/gce/examples/websocket/server.go b/controllers/gce/examples/websocket/server.go new file mode 100644 index 000000000..0e9700cab --- /dev/null +++ b/controllers/gce/examples/websocket/server.go @@ -0,0 +1,81 @@ +package main + +import ( + "fmt" + "log" + "net/http" + "os" + "time" + + "github.com/gorilla/websocket" +) + +var podName string +var upgrader = websocket.Upgrader{ + CheckOrigin: func(r *http.Request) bool { + return true // Ignore http origin + }, +} + +func init() { + podName = os.Getenv("podname") +} + +func ws(w http.ResponseWriter, r *http.Request) { + log.Println("Received request", r.RemoteAddr) + c, err := upgrader.Upgrade(w, r, nil) + if err != nil { + log.Println("failed to upgrade:", err) + return + } + defer c.Close() + + s := fmt.Sprintf("Connected to %v", podName) + c.WriteMessage(websocket.TextMessage, []byte(s)) + handleWSConn(c) +} + +func handleWSConn(c *websocket.Conn) { + stop := make(chan struct{}) + go func() { + for { + time.Sleep(5 * time.Second) + + select { + case <-stop: + return + default: + } + + s := fmt.Sprintf("%s reports time: %v", podName, time.Now().String()) + c.WriteMessage(websocket.TextMessage, []byte(s)) + } + }() + for { + mt, message, err := c.ReadMessage() + if err != nil { + log.Println("Error while reading:", err) + break + } + if err = c.WriteMessage(mt, message); err != nil { + log.Println("Error while writing:", err) + break + } + } + close(stop) +} + +func root(w http.ResponseWriter, r *http.Request) { + if r.URL.Path != "/" { + http.NotFound(w, r) + return + } + w.Write([]byte(`Websocket example. Connect to /ws`)) +} + +func main() { + log.Println("Starting") + http.HandleFunc("/ws", ws) + http.HandleFunc("/", root) + log.Fatal(http.ListenAndServe(":8080", nil)) +} diff --git a/docs/faq/gce.md b/docs/faq/gce.md index ed0fe3796..122556f10 100644 --- a/docs/faq/gce.md +++ b/docs/faq/gce.md @@ -26,6 +26,7 @@ Table of Contents * [What GCE resources are shared between Ingresses?](#what-gce-resources-are-shared-between-ingresses) * [How do I debug a controller spin loop?](#host-do-i-debug-a-controller-spinloop) * [Creating an Internal Load Balancer without existing ingress](#creating-an-internal-load-balancer-without-existing-ingress) +* [Can I use websockets?](#can-i-use-websockets) ## How do I deploy an Ingress controller? @@ -380,3 +381,9 @@ kubectl get nodes gcloud compute instance-groups unmanaged add-instances $GROUPNAME --zone {ZONE} --instances=A,B,C... ``` You can now follow the GCP Console wizard for creating an internal load balancer and point to the `k8s-ig--{UID}` instance group. + +## Can I use websockets? +Yes! +The GCP HTTP(S) Load Balancer supports websockets. You do not need to change your http server or Kubernetes deployment. You will need to manually configure the created Backend Service's `timeout` setting. This value is the interpreted as the max connection duration. The default value of 30 seconds is probably too small for you. You can increase it to the supported maximum: 86400 (a day) through the GCP Console or the gcloud CLI. + +View the [example](/controllers/gce/examples/websocket/).