To deploy a function you use the kubeless CLI. You need to specify a runtime which specifies which language your function is in. You need to specify the file that contains your function, how the function will get triggered (here we use an HTTP trigger) and finally you specify the function name as a handler.

kubeless function deploy toy --runtime python2.7 \ --handler toy.handler \ --from-file toy.py

You can then list the function with the kubeless CLI:

kubeless function ls

While the function get deployed you can check the actual Python function:

cat toy.py

Under the hood, Kubeless automatically created a Kubernetes deployment and service. You can check that a Pod containing your function is running:

kubectl get pods

You can call the function using the kubeless CLI convenience wrapper:

kubeless function call toy --data '{"hello":"world"}'

Or you can call the service endpoint if you have a proxy running.

Let's run a proxy:

kubectl proxy --port 8080 &

And now let's call the function directly via curl:

curl --data '{"hello":"world"}' localhost:8080/api/v1/namespaces/default/services/toy:8080/proxy/ --header "Content-Type:application/json"

You can get the logs of the function

kubeless function logs toy

As well as get the description of it

kubeless function describe toy

To update a function use the kubeless function update command. For example to replace the toy function with the method from the toy-udpate.py script, do:

kubeless function update toy --from-file toy-update.py

If you check the content of the new function you will see that it hard codes the JSON object being returned:

cat toy-update.py

Under the hood, Kubernetes will do a rolling update of the Pods making up your function. Once this is finished, you can call your function and see that the new function is now deployed.

kubeless function call toy --data '{"hello":"world"}'

There are additional runtimes. In addition to Python 2.7 and 3.4 you can also deploy Ruby, Node and .Net core functions.

Let's deploy a toy Node.js function.

cat hello.js

You can deploy this function like so:

kubeless function deploy hello --runtime nodejs6 \ --handler hello.handler \ --from-file hello.js

You can list it

kubeless function ls

And call it as well

kubeless function call hello --data '{"kubeless":"rocks"}'

Once you are done you can remove the functions

kubeless function delete toy

and

kubeless function delete hello

The deployment and Kubernetes services will be removed automatically

kubectl get deployments,services