docs/serving/samples/autoscale-go

Autoscale Sample

A demonstration of the autoscaling capabilities of an Knative Serving Revision.

Prerequisites

1. A Kubernetes cluster with Knative Serving installed.
2. Install Docker.
3. Check out the code:

go get -d github.com/knative/docs/serving/samples/autoscale-go

Setup

Build the application container and publish it to a container registry:

1. Move into the sample directory:

   cd $GOPATH/src/github.com/knative/docs
   

2. Set your preferred container registry:

   export REPO="gcr.io/<YOUR_PROJECT_ID>"
   

   • This example shows how to use Google Container Registry (GCR). You will need a Google Cloud Project and to enable the Google Container Registry API.

3. Use Docker to build your application container:

   docker build \
     --tag "${REPO}/serving/samples/autoscale-go" \
     --file=serving/samples/autoscale-go/Dockerfile .
   

4. Push your container to a container registry:

   docker push "${REPO}/serving/samples/autoscale-go"
   

5. Replace the image reference with our published image:

   perl -pi -e \
   "s@github.com/knative/docs/serving/samples/autoscale-go@${REPO}/serving/samples/autoscale-go@g" \
   serving/samples/autoscale-go/sample.yaml
   

Deploy the Service

1. Deploy the Knative Serving sample:

   kubectl apply -f serving/samples/autoscale-go/sample.yaml
   

2. Find the ingress hostname and IP and export as an environment variable:

   export SERVICE_HOST=`kubectl get route autoscale-route -o jsonpath="{.status.domain}"`
   export SERVICE_IP=`kubectl get svc knative-ingressgateway -n istio-system -o jsonpath="{.status.loadBalancer.ingress[*].ip}"`
   

View the Autoscaling Capabilities

1. Request the largest prime less than 40,000,000 from the autoscale app. Note that it consumes about 1 cpu/sec.

   time curl --header "Host:$SERVICE_HOST" http://${SERVICE_IP?}/primes/40000000
   

2. Ramp up traffic on the autoscale app (about 300 QPS):

   kubectl delete namespace hey --ignore-not-found && kubectl create namespace hey
   

   for i in `seq 2 2 60`; do
       kubectl -n hey run hey-$i --image josephburnett/hey --restart Never -- \
         -n 999999 -c $i -z 2m -host $SERVICE_HOST \
         "http://${SERVICE_IP?}/primes/40000000"
       sleep 1
   done
   

3. Watch the Knative Serving deployment pod count increase.

   kubectl get deploy --watch
   

   Note: Use CTRL+C to exit watch mode.

4. Watch the pod traffic ramp up.

   kubectl get pods -n hey --show-all --watch
   

5. Look at the latency, requests/sec and success rate of each pod.

   for i in `seq 2 2 60`; do kubectl -n hey logs hey-$i ; done
   

Cleanup

kubectl delete namespace hey
kubectl delete -f serving/samples/autoscale-go/sample.yaml