Chapter 2. Creating functions

Prerequisites

• The OpenShift Serverless Operator and Knative Serving are installed on the cluster.
• You have installed the Knative (kn) CLI.

Procedure

• Create a function project:

  $ kn func create -r <repository> -l <runtime> -t <template> <path>

  • Accepted runtime values include quarkus, node, typescript, go, python, springboot, and rust.

  • Accepted template values include http and cloudevents.

    Example command

    $ kn func create -l typescript -t cloudevents examplefunc

    Example output

    Created typescript function in /home/user/demo/examplefunc

  • Alternatively, you can specify a repository that contains a custom template.

    Example command

    $ kn func create -r https://github.com/boson-project/templates/ -l node -t hello-world examplefunc

    Example output

    Created node function in /home/user/demo/examplefunc

Prerequisites

• Before you can create a function by using the web console, a cluster administrator must complete the following steps:

  • Install the OpenShift Serverless Operator and Knative Serving on the cluster.
  • Install the OpenShift Pipelines Operator on the cluster.

  • Create the following pipeline tasks so that they are available for all namespaces on the cluster:

    func-s2i and func-deploy tasks

    $ kn func tkn-tasks | oc apply -f -

    Node.js function

    $ oc apply -f https://raw.githubusercontent.com/openshift-knative/kn-plugin-func/serverless-1.34/pkg/pipelines/resources/tekton/pipeline/dev-console/0.1/nodejs-pipeline.yaml

• You must log into the OpenShift Container Platform web console.
• You must create a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.
• You must create or have access to a Git repository that contains the code for your function. The repository must contain a func.yaml file and use the s2i build strategy.

Verification

• After you have created a function, you can view it in the Topology view of the Developer perspective.