websocket

README

Simple Websocket Example

Any websocket server will suffice; however, for the purpose of demonstration, we'll use the gorilla/websocket package in a Go binary.

Build

➜ CGO_ENABLED=0 go build -o wsserver

Containerize

➜ docker build -t [YOUR_IMAGE] .
...
➜ docker push [YOUR_IMAGE]
...

Deploy

Either update the image in the Deployment to your newly created image.

➜ vi deployment.yaml
# Change image to your own

➜ 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:

➜ 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. Visit http://xxx.xxx.xxx.xxx and click 'Connect'. You should receive messages from server with timestamps.

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.

➜  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.

➜ 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.