Autoscaling in Action

Remember those super powers we talked about? One of Knative Serving's powers is autoscaling. This means your Knative Service will only "spin up" to preform its job (in this case, saying "Hello world!") if it is needed, otherwise, it will spin down and wait for a new request to come in.

Let's see this in action! We're going to peek under the hood at the Pods in Kubernetes where our Knative Service is running to watch our "Hello world!" Service scale up and down.

Check the Knative Pods

Let's run our "Hello world!" Service just one more time. This time, try the Knative Service URL in your browser or by using open instead of curl in your CLI.

open <service-url>

Where <service-url> is the URL where your Knative Service was deployed (same as the <service-url> in the last step).

You can watch the pods and see how they scale down to zero after http traffic stops to the url

kubectl get pod -l serving.knative.dev/service=hello -w

The output should look like this:

NAME                                     READY   STATUS
hello-xxxxx-1                           2/2     Running
hello-xxxxx-1                           2/2     Terminating
hello-xxxxx-1                           1/2     Terminating
hello-xxxxx-1                           0/2     Terminating

Try to access the url again, and you will see a new pod running again.

NAME                                     READY   STATUS
hello-xxxxx-1                           0/2     Pending
hello-xxxxx-1                           0/2     ContainerCreating
hello-xxxxx-1                           1/2     Running
hello-xxxxx-1                           2/2     Running

Some people call this Serverless