Container Service for Kubernetes:Deploy Knative Functions

Prerequisites

Before you begin, make sure you have:

• Knative deployed in your ACK cluster. For setup instructions, see Deploy and manage Knative

Step 1: Install the func CLI

Download the func binary from the func release page and select the binary for your operating system.

The following example installs func on Linux:

1. Rename the binary to func:

   mv <path-to-binary-file> func

   Replace <path-to-binary-file> with the path to the downloaded binary, for example, func_linux_amd64.

2. Make the binary executable:

   chmod +x func

3. Move the binary to a directory in your PATH:

   mv func /usr/local/bin

4. Verify the installation:

   func version

   If version information is returned, func is installed successfully.

Step 2: Create a function

Knative Functions supports the following runtimes, all of which work with both HTTP and CloudEvent invocations:

• Node.js

• Python

• Go

• Quarkus

• Rust

• Spring Boot

• TypeScript

The following steps use Go as an example.

1. Create a function:

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

   For example, create a Go function named hello:

   func create -l go hello

   Expected output:

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

2. List the project files in the hello directory:

   ls hello/

   Expected output:

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

3. Review the auto-generated func.yaml in the hello directory:

   cat func.yaml

   Expected output:

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

4. Edit func.yaml to configure the registry and deployment settings. The following is an example of a complete func.yaml:

   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

   Key fields:

   Field	Description
   registry	The container registry where built images are pushed. Example: registry.cn-beijing.aliyuncs.com/knative-release-xxx
   build.builderImages.pack	The builder image used to build the function. Example: registry-cn-beijing.ack.aliyuncs.com/acs/knative-func-builder-jammy-tiny:latest
   deploy.namespace	The Kubernetes namespace where the function is deployed

   For a full list of func.yaml options, see the func.yaml reference.

Step 3: Deploy the function

Run func deploy from inside the hello directory. The command uses the function project name as the Knative Service name and combines the project name with the registry to construct the full image address.

func deploy

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

After deployment, verify the function details:

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 the function

1. Add an entry to your hosts file to route the Knative Service domain name to the Knative gateway IP address:

   121.xx.xxx.xx hello.default.example.com

   Replace 121.xx.xxx.xx with the actual Knative gateway IP address and hello.default.example.com with the domain name shown in the deployment output.

2. 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 confirms that an HTTP request was successfully sent to and handled by the function.

3. Verify that pods were created for the function:

   kubectl get pod

   Expected output:

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

What's next

For answers to common questions about Knative in ACK, see Knative FAQ.