Container Service for Kubernetes:Deploy Knative Functions

Step 1: Download and install a command-line tool

1. Go to the funcrelease page and download a binary file of the func command-line tool based on the OS that you use.

   The following example shows how to install func on Linux.

2. After you download the binary file, run the following command to rename the file as func:

   mv <path-to-binary-file> func # <path-to-binary-file> is the local path of the binary file. Example: func_darwin_amd64 or func_linux_amd64.

3. Run the following command to make the file executable:

   chmod +x func

4. Run the following command to move the func binary file to a directory that is contained in the PATH variable of Linux. This way, the binary file can be executed from any path.

   mv func /usr/local/bin

5. Run the following command to check whether func is installed:

   func version

   If information about the func version is returned, func is installed.

Step 2: Create a function

Knative Functions provides templates that can be used to create basic functions. You can select the following templates based on the programming language and invocation method that you want to use. The following templates allow you to invoke a function by using CloudEvent and HTTP requests.

• Node.js

• Python

• Go

• Quarkus

• Rust

• Spring Boot

• TypeScript

The following example shows how to use a Go template to create a function.

1. Run the following command to create a function:

   func create -l <language> <function-name>

   For example, create a demo function written in Go.

   func create -l go hello

   Expected output:

   Created go function in /usr/local/bin/hello

2. Run the ls command in the hello directory to query the project directory that is created:

   func.yaml  go.mod  handle.go  handle_test.go  README.md

3. Run the following command in the hello directory to query the func.yaml file that is automatically created:

   cat func.yaml

   Expected output:

   specVersion: 0.35.0
   name: hello
   runtime: go
   created: 2023-12-13T06:48:45.419587147Z

4. Modify the func.yaml file by customizing parameters for function building and deployment. The func.yaml file contains the configurations of the function project. For more information, see func_yaml.md.

   The following code block provides an example of the func.yaml file:

   specVersion: 0.35.0
   name: hello
   runtime: go
   created: 2023-11-29T14:47:34.101658+08:00
   registry: registry.cn-beijing.aliyuncs.com/knative-release-xxx
   image: registry.cn-beijing.aliyuncs.com/knative-release-xxx/hello:latest
   build:
     builderImages:
       pack: registry-cn-beijing.ack.aliyuncs.com/acs/knative-func-builder-jammy-tiny:latest
   deploy:
     namespace: default

   • registry: the registry to which images are pushed after they are built.

   • builderImages: the image used by the image builder. Example: registry-cn-beijing.ack.aliyuncs.com/acs/knative-func-builder-jammy-tiny:latest.

   • deploy: the configurations for deploying the function, such as the namespace where the function is deployed.

Step 3: Deploy to Knative Functions

You can deploy the function after it is created.

1. Run the following command to deploy a function.

   By default, the deploy command deploys the function as a Knative Service that is named after the function project. The project name and registry name are used to generate the full image address when the function is built.

   func deploy

   Expected output:

   Building function image
   Still building
   Still building
   Yes, still building
   Don't give up on me
   Still building
   This is taking a while
   Still building
   Still building
   Yes, still building
   Function built: registry.cn-beijing.aliyuncs.com/knative-release-xxx/hello:latest
   Pushing function image to the registry "registry.cn-beijing.aliyuncs.com" using the "xxx" user credentials
   Deploying function to the cluster
   Function deployed in namespace "default" and exposed at URL:
      http://hello.default.example.com

2. Run the following command to query the function that is deployed:

   func info

   Expected output:

   Function name:
     hello
   Function is built in image:
   
   Function is deployed in namespace:
     default
   Routes:
     http://hello.default.example.com

Step 4: Invoke from Knative Functions

1. Add the following configuration to the hosts file to point the domain name of the Knative Service to the IP address of the Knative gateway. Example:

   121.xx.xxx.xx hello.default.example.com # Replace 121.xx.xxx.xx with the actual Knative gateway IP address. Replace hello.default.example.com with the domain name of the Knative Service.

2. Run the following command to invoke the function:

   func invoke

   Expected output:

   POST / HTTP/1.1 hello.default.example.com
     Content-Type: application/json
     Forwarded: for=192.168.102.101;proto=http
     Knative-Serving-Default-Route: true
     X-Forwarded-Proto: http
     User-Agent: Go-http-client/1.1
     Content-Length: 25
     Accept-Encoding: gzip
     K-Proxy-Request: activator
     X-Forwarded-For: 192.168.102.101, 192.168.102.97
     X-Request-Id: 3d82cfc8-f9df-4935-84cd-c6561b4587f6
   Body:

   The output shows that an HTTP request is sent to the Knative Functions and the function is successfully invoked.

3. Run the following command to query pods in the cluster:

   kubectl get pod

   Expected output:

   NAME                                      READY   STATUS    RESTARTS   AGE
   hello-00001-deployment-7b65fcdc4c-gfcbp   2/2     Running   0          34

   The output shows that pods are created after the invocation.