Quickstarts

• 1: Prerequisites
• 2: Create Sync Functions
• 3: Create Async Functions
• 4: Create Serverless Applications
• 5: Create Wasm Functions

1 - Prerequisites

Registry Credential

When building a function, you’ll need to push your function container image to a container registry like Docker Hub or Quay.io. To do that you’ll need to generate a secret for your container registry first.

You can create this secret by filling in the REGISTRY_SERVER, REGISTRY_USER and REGISTRY_PASSWORD fields, and then run the following command.

REGISTRY_SERVER=https://index.docker.io/v1/
REGISTRY_USER=<your_registry_user>
REGISTRY_PASSWORD=<your_registry_password>
kubectl create secret docker-registry push-secret \
 --docker-server=$REGISTRY_SERVER \
 --docker-username=$REGISTRY_USER \
 --docker-password=$REGISTRY_PASSWORD

Source repository Credential

If your source code is in a private git repository, you’ll need to create a secret containing the private git repo’s username and password:

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: git-repo-secret
  annotations:
    build.shipwright.io/referenced.secret: "true"
type: kubernetes.io/basic-auth
stringData:
  username: <cleartext username>
  password: <cleartext password>
EOF

You can then reference this secret in the Function CR’s spec.build.srcRepo.credentials

apiVersion: core.openfunction.io/v1beta1
kind: Function
metadata:
  name: function-sample
spec:
  version: "v2.0.0"
  image: "openfunctiondev/sample-go-func:v1"
  imageCredentials:
    name: push-secret
  build:
    builder: openfunction/builder-go:latest
    env:
      FUNC_NAME: "HelloWorld"
      FUNC_CLEAR_SOURCE: "true"
    srcRepo:
      url: "https://github.com/OpenFunction/samples.git"
      sourceSubPath: "functions/knative/hello-world-go"
      revision: "main"
      credentials:
         name: git-repo-secret
  serving:
    template:
      containers:
        - name: function # DO NOT change this
          imagePullPolicy: IfNotPresent 
    runtime: "knative"

Kafka

Async functions can be triggered by events in message queues like Kafka, here you can find steps to setup a Kafka cluster for demo purpose.

1. Install strimzi-kafka-operator in the default namespace.

   helm repo add strimzi https://strimzi.io/charts/
   helm install kafka-operator -n default strimzi/strimzi-kafka-operator
   

2. Run the following command to create a Kafka cluster and Kafka Topic in the default namespace. The Kafka and Zookeeper clusters created by this command have a storage type of ephemeral and are demonstrated using emptyDir.

   Here we create a 1-replica Kafka server named <kafka-server> and a 1-replica topic named <kafka-topic> with 10 partitions

   cat <<EOF | kubectl apply -f -
   apiVersion: kafka.strimzi.io/v1beta2
   kind: Kafka
   metadata:
     name: <kafka-server>
     namespace: default
   spec:
     kafka:
       version: 3.3.1
       replicas: 1
       listeners:
         - name: plain
           port: 9092
           type: internal
           tls: false
         - name: tls
           port: 9093
           type: internal
           tls: true
       config:
         offsets.topic.replication.factor: 1
         transaction.state.log.replication.factor: 1
         transaction.state.log.min.isr: 1
         default.replication.factor: 1
         min.insync.replicas: 1
         inter.broker.protocol.version: "3.1"
       storage:
         type: ephemeral
     zookeeper:
       replicas: 1
       storage:
         type: ephemeral
     entityOperator:
       topicOperator: {}
       userOperator: {}
   ---
   apiVersion: kafka.strimzi.io/v1beta2
   kind: KafkaTopic
   metadata:
     name: <kafka-topic>
     namespace: default
     labels:
       strimzi.io/cluster: <kafka-server>
   spec:
     partitions: 10
     replicas: 1
     config:
       cleanup.policy: delete
       retention.ms: 7200000
       segment.bytes: 1073741824
   EOF
   

3. Run the following command to check Pod status and wait for Kafka and Zookeeper to run and start.

   $ kubectl get po
   NAME                                              READY   STATUS        RESTARTS   AGE
   <kafka-server>-entity-operator-568957ff84-nmtlw   3/3     Running       0          8m42s
   <kafka-server>-kafka-0                            1/1     Running       0          9m13s
   <kafka-server>-zookeeper-0                        1/1     Running       0          9m46s
   strimzi-cluster-operator-687fdd6f77-cwmgm         1/1     Running       0          11m
   

   Run the following command to view the metadata for the Kafka cluster.

   $ kafkacat -L -b <kafka-server>-kafka-brokers:9092
   

WasmEdge

Function now supports using WasmEdge as workload runtime, here you can find steps to setup the WasmEdge workload runtime in a Kubernetes cluster (with containerd as the container runtime).

You should run the following steps on all the nodes (or a subset of the nodes that will host the wasm workload) of your cluster.

Step 1 : Installing WasmEdge

The easiest way to install WasmEdge is to run the following command. Your system should have git and curl installed.

wget -qO- https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash -s -- -p /usr/local

Step 2 : Installing Container runtimes

crun

The crun project has WasmEdge support baked in. For now, the easiest approach is just download the binary and move it to /usr/local/bin/

wget https://github.com/OpenFunction/OpenFunction/releases/latest/download/crun-linux-amd64
mv crun-linux-amd64 /usr/local/bin/crun

If the above approach does not work for you, please refer to build and install a crun binary with WasmEdge support.

Step 3 : Setup CRI runtimes

Option 1: containerd

You can follow this installation guide to install containerd and this setup guide to setup containerd for Kubernetes.

First, edit the configuration /etc/containerd/config.toml, add the following section to setup crun runtime, make sure the BinaryName equal to your crun binary path

# Add crun runtime here
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.crun]
  runtime_type = "io.containerd.runc.v2"
  pod_annotations = ["*.wasm.*", "wasm.*", "module.wasm.image/*", "*.module.wasm.image", "module.wasm.image/variant.*"]
  privileged_without_host_devices = false
  [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.crun.options]
    BinaryName = "/usr/local/bin/crun"

Next, restart containerd service:

sudo systemctl restart containerd

Option 2: CRI-O

You can follow this installation guide to install CRI-O and this setup guide to setup CRI-O for Kubernetes.

CRI-O uses the runc runtime by default and we need to configure it to use crun instead. That is done by adding to two configuration files.

First, create a /etc/crio/crio.conf file and add the following lines as its content. It tells CRI-O to use crun by default.

[crio.runtime]
default_runtime = "crun"

The crun runtime is in turn defined in the /etc/crio/crio.conf.d/01-crio-runc.conf file.

[crio.runtime.runtimes.runc]
runtime_path = "/usr/lib/cri-o-runc/sbin/runc"
runtime_type = "oci"
runtime_root = "/run/runc"
# The above is the original content

# Add crun runtime here
[crio.runtime.runtimes.crun]
runtime_path = "/usr/local/bin/crun"
runtime_type = "oci"
runtime_root = "/run/crun"

Next, restart CRI-O to apply the configuration changes.

systemctl restart crio

2 - Create Sync Functions

Before you creating any functions, make sure you’ve installed all the prerequisites

Sync functions are functions whose inputs are payloads of HTTP requests, and the output or response are sent to the waiting client immediately after the function logic finishes processing the inputs payload. Below you can find some sync function examples in different languages:

You can find more function samples here

3 - Create Async Functions

Before you creating any functions, make sure you’ve installed all the prerequisites

Async functions are event-driven and their inputs are usually events from Non-HTTP event sources like message queues, cron triggers, MQTT brokers etc. and usually the client will not wait for an immediate response after triggering an async function by delivering an event. Below you can find some async function examples in different languages:

You can find more function samples here

4 - Create Serverless Applications

Before you creating any functions, make sure you’ve installed all the prerequisites

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

Here you can find several Serverless Application examples:

You can find more info about these Serverless Applications here

5 - Create Wasm Functions

Before you creating any functions, make sure you’ve installed all the prerequisites

Here you can find wasm function examples:

You can find more info about these Function here