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Connect to the Contrast Coordinator

This step describes how to connect to a running Contrast Coordinator.

Applicability​

This step is necessary for interacting with the Coordinator, which we'll need to be doing in some of the following steps. In particular, a way to communicate with the Coordinator is required for setting the manifest and for verifying the deployment, two essential steps when working with Contrast.

Prerequisites​

  1. Set up cluster
  2. Install CLI
  3. Deploy the Contrast runtime
  4. Add Coordinator to resources
  5. Prepare deployment files
  6. Configure TLS (optional)
  7. Enable GPU support (optional)
  8. Generate annotations and manifest
  9. Deploy application

How-to​

The released Coordinator resource includes a LoadBalancer definition. Communication with the Coordinator can be handled via the ingress IP of the load balancer. Store this IP in an environment variable for use in the following steps:

coordinator=$(kubectl get svc coordinator -o=jsonpath='{.status.loadBalancer.ingress[0].ip}')

Port forwarding​

If you can't use a public load balancer, you can deploy a port-forwarding pod to relay traffic to a Contrast pod instead:

apiVersion: v1
kind: Pod
metadata:
  name: port-forwarder-coordinator
spec:
  containers:
    - name: port-forwarder
      image: "alpine/socat@sha256:..."
      args:
        - -d
        - TCP-LISTEN:1313,fork
        - TCP:coordinator:1313
      resources:
        requests:
          memory: 50Mi
        limits:
          memory: 50Mi

This is currently required because kubectl port-forward uses a Container Runtime Interface (CRI) method that isn't supported by the Kata shim. Upstream tracking issue: https://github.com/kata-containers/kata-containers/issues/1693.