Serverless Applications

In addition to building and running Serverless Functions, you can also build and run Serverless Applications with OpenFuntion.

OpenFunction support building source code into container images in two different ways:

• Using Cloud Native Buildpacks to build source code without a Dockerfile
• Using Buildah or BuildKit to build source code with a Dockerfile

To push images to a container registry, you’ll need to create a secret containing the registry’s credential and add the secret to imageCredentials. Please refer to the prerequisites section for more info.

Build and run a Serverless Application with a Dockerfile

If you already created a Dockerfile for your application like this Go Application, you can build and run this application in the serverless way like this:

1. Create the sample go serverless application

cat <<EOF | kubectl apply -f -
apiVersion: core.openfunction.io/v1beta1
kind: Function
metadata:
  name: sample-go-app
spec:
  version: "v1.0.0"
  image: "openfunctiondev/sample-go-app:v1"
  imageCredentials:
    name: push-secret
  #port: 8080 # default to 8080
  build:
    builder: openfunction/buildah:v1.23.1
    srcRepo:
      url: "https://github.com/OpenFunction/samples.git"
      sourceSubPath: "apps/buildah/go"
      revision: "main"
    shipwright:
      strategy:
        name: buildah
        kind: ClusterBuildStrategy
  serving:
    runtime: knative
    template:
      containers:
        - name: function
          imagePullPolicy: IfNotPresent
EOF

1. Check the application status

You can then check the serverless app’s status by kubectl get functions.core.openfunction.io -w:

kubectl get functions.core.openfunction.io -w
NAME                    BUILDSTATE   SERVINGSTATE   BUILDER         SERVING         ADDRESS                                                   AGE
sample-go-app           Succeeded    Running        builder-jgnzp   serving-q6wdp   http://sample-go-app.default.svc.cluster.local/           22m

1. Access this application

Once the BUILDSTATE becomes Succeeded and the SERVINGSTATE becomes Running, you can access this Go serverless app through the address in the ADDRESS field:

kubectl run curl --image=radial/busyboxplus:curl -i --tty
curl http://sample-go-app.default.svc.cluster.local

Here you can find a Java Serverless Applications (with a Dockerfile) example.

Build and run a Serverless Application without a Dockerfile

If you hava an application without a Dockerfile like this Java Application, you can also build and run your application in the serverless way like this Java application:

1. Create the sample Java serverless application

cat <<EOF | kubectl apply -f -
apiVersion: core.openfunction.io/v1beta1
kind: Function
metadata:
  name: sample-java-app-buildpacks
spec:
  version: "v1.0.0"
  image: "openfunction/sample-java-app-buildpacks:v1"
  imageCredentials:
    name: push-secret
  port: 8080 # default to 8080
  build:
    builder: "cnbs/sample-builder:alpine"
    srcRepo:
      url: "https://github.com/buildpacks/samples.git"
      sourceSubPath: "apps/java-maven"
      revision: "main"
  serving:
    runtime: "knative" # default to knative
    template:
      containers:
        - name: function
          imagePullPolicy: IfNotPresent
EOF

1. Check the application status

You can then check the serverless app’s status by kubectl get functions.core.openfunction.io -w:

kubectl get functions.core.openfunction.io -w
NAME                                 BUILDSTATE   SERVINGSTATE   BUILDER         SERVING         ADDRESS                                                                AGE
sample-java-app-buildpacks           Succeeded    Running        builder-jgnzp   serving-q6wdp   http://sample-java-app-buildpacks.default.svc.cluster.local/           22m

1. Access this application

Once the BUILDSTATE becomes Succeeded and the SERVINGSTATE becomes Running, you can access this Java serverless app through the address in the ADDRESS field:

kubectl run curl --image=radial/busyboxplus:curl -i --tty
curl http://sample-java-app-buildpacks.default.svc.cluster.local