Chapter 22. Exposing services on the application network using YAML

Create a workload that you want to expose on the network, for example:

kubectl create deployment backend --image quay.io/skupper/hello-world-backend --replicas 3

Create a connector resource YAML file:

apiVersion: skupper.io/v2alpha1
kind: Connector
metadata:
  name: backend
  namespace: east
spec:
  routingKey: backend
  selector: app=backend
  port: 8080

This creates a connector in the east site and exposes the backend deployment on the network on port 8080. You can create a listener on a different site using the matching routing key backend to address this service.

To create the connector resource:

skupper system apply -f <filename>

where <filename> is the name of a YAML file that is saved on your local filesystem.

Check the connector status:

skupper connector status

For example:

NAME    STATUS  ROUTING-KEY     SELECTOR        HOST    PORT    HAS MATCHING LISTENER    MESSAGE
backend Pending backend         app=backend             8080    false   No matching listeners

📌 NOTE By default, the routing key name is set to the name of the connector. If you want to use a custom routing key, set spec.routingKey to your custom value.

Create a listener resource YAML file:

apiVersion: skupper.io/v2alpha1
kind: Listener
metadata:
  name: backend
  namespace: west
spec:
  routingKey: backend
  host: east-backend
  port: 8080

This creates a listener on the local system site and matches it with connectors that use the routing key backend. The listener accepts connections on port 8080 using the configured host value.

To create the listener resource:

skupper system apply -f <filename>

where <filename> is the name of a YAML file that is saved on your local filesystem.

Check the listener status:

skupper listener status

For example:

NAME      STATUS  ROUTING-KEY  HOST     PORT  MATCHING-CONNECTOR  MESSAGE
backend   Ready   backend      0.0.0.0  8080  true                OK

📌 NOTE There must be a MATCHING-CONNECTOR for the service to operate.

Create a multi-key listener resource YAML file. For example:

apiVersion: skupper.io/v2alpha1
kind: MultiKeyListener
metadata:
  name: mkl-backend
spec:
  host: mkl-backend
  port: 9092
  strategy:
    weighted:
      routingKeys:
        east-backend: 1
        west-backend: 1

This creates a listener named mkl-backend that exposes a single endpoint on port 9092 and distributes traffic evenly across the east-backend and west-backend routing keys.

To prefer one routing key first and fall back to another, use the priority strategy:

apiVersion: skupper.io/v2alpha1
kind: MultiKeyListener
metadata:
  name: mkl-backend-priority
spec:
  host: mkl-backend-priority
  port: 9095
  strategy:
    priority:
      routingKeys:
        - east-backend-http
        - west-backend-http

To create the multi-key listener resource:

skupper system apply -f <filename>

where <filename> is the name of a YAML file that is saved on your local filesystem.

📌 NOTE If you need to change strategy after you created a multi-key listener, you must delete and recreate the resource. This does not affect changing routing keys or weights.