Using extensions enabled by QPOptions

QPOptions is a Queue Proxy feature that enables extending Queue Proxy with additional Go packages. For example, the security-guard repository extends Queue Proxy by adding runtime security features to protect user services.

Once your cluster is setup with extensions enabled by QPOptions, a Service can decide which extensions it wish to use and how to configure such extensions. Activating and configuring extensions is described here.

Overview

A Service can activate and configure extensions by adding qpoption.knative.dev/* annotations under the: spec.template.metadata of the Service Custom Resource Definition (CRD).

Setting a value of: qpoption.knative.dev/<ExtensionName>-activate: "enable" activates the extension.

Setting a value of: qpoption.knative.dev/<extension-name>-config-<key>: "<value>" adds a configuration of key: value to the extension.

In addition, the Service must ensure that the Pod Info volume is mounted by adding the features.knative.dev/queueproxy-podinfo: enabled annotation under the: spec.template.metadata of the Service CRD.

You can create a Knative Service by applying a YAML file or by using the kn service create CLI command.

Prerequisites

Before you can use extensions enabled by QPOptions, you must:

• Prepare your cluster:
• Make sure you are using a Queue Proxy image that was built with the extensions that you wish to use - See Extending Queue Proxy image with QPOptions.
• Make sure that the cluster config-features is set with queueproxy.mount-podinfo: allowed. See Enabling Queue Proxy Pod Info for more details.
• Meet the prerequisites in Creating a Service

Procedure

Tip

The following commands create a helloworld-go sample Service while activating and configuring the test-gate extension for this Service. You can modify these commands, including the extension(s) to be activated and the extension configuration.

Create a sample Service:

Apply YAMLkn CLI

1. Create a YAML file using the following example:

   apiVersion: serving.knative.dev/v1
   kind: Service
   metadata:
     name: helloworld-go
     namespace: default
   spec:
     template:
       metadata:
           annotations:
             features.knative.dev/queueproxy-podinfo: enabled
             qpoption.knative.dev/testgate-activate: enable
             qpoption.knative.dev/testgate-config-response: CU
             qpoption.knative.dev/testgate-config-sender: Joe
       spec:
         containers:
           - image: gcr.io/knative-samples/helloworld-go
             env:
               - name: TARGET
                 value: "World"
   

2. Apply the YAML file by running the command:

   kubectl apply -f <filename>.yaml
   

   Where <filename> is the name of the file you created in the previous step.

kn service create helloworld-go \
    --image gcr.io/knative-samples/helloworld-go \
    --env TARGET=World \
    --annotation features.knative.dev/queueproxy-podinfo=enabled \
    --annotation qpoption.knative.dev/testgate-activate=enable \
    --annotation qpoption.knative.dev/testgate-config-response=Goodbye \
    --annotation qpoption.knative.dev/testgate-config-sender=Joe

After the Service has been created, Knative propagates the annotations to the podSpec of the Service deployment. When a Service pod is created, the Queue Proxy sidecar will mount a volume that contains the pod annotations and activate the testgate extension. This occurs if the testgate extension is available in the Queue Proxy image. The testgate extension will then be configured with the configuration: { sender: "Joe", response: "CU"}.