Support for pinning the IP address of the load balancer via terraform overrides

[aktech]

Fixes | Closes | Resolves #1210

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Changes introduced in this PR:

• Adds support for terraform overrides in ingress's load balancer.

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[costrouc]

I agree with all the terraform modifications. Would like the python side of things to be more flexible. This allows us keep the schema for qhub simpler.

[costrouc]

I'd prefer if this is terraform_overrides: Any and we defer to terraform for the checks.

[costrouc]

So no need for the IngressTerraformOverrides

[aktech]

The problem with this is, "Any" won't reach terraform, as we parse these in the input_vars.py, so anything other than this won't be passed, unless we pass them explicitly.

[aktech]

Ah, I see your comment below now.

[costrouc]

Using what I showed above we just supply terraform_overrides e.g. **config.get("ingress", {}).get("terraform_overrides": {}). Terraform variables will do all the checking for us.

[aktech]

The problem is, we need load-balancer-ip and load-balancer-annotations separately, to be passed to different variables, so that they can be used at their designated places:

In qhub/template/stages/04-kubernetes-ingress/modules/kubernetes/ingress/main.tf

spec:

  spec {
    selector = merge({
      "app.kubernetes.io/component" = "traefik-ingress"
    }, var.load-balancer-annotations)

and

    type = "LoadBalancer"
    load_balancer_ip = var.load-balancer-ip

[costrouc]

I think this should work. Suppose

ingress:
  terraform_overrides:
      load-balancer-annotations:
           k1: v1
           k2: v2
      load-balancer-ip: 1.2.3.4

Then in input-vars.py we supply:

    return {
        "name": config["project_name"],
        "environment": config["namespace"],
        "node_groups": _calculate_note_groups(config),
        "enable-certificates": (config["certificate"]["type"] == "lets-encrypt"),
        "acme-email": config["certificate"].get("acme_email"),
        "acme-server": config["certificate"].get("acme_server"),
        "certificate-secret-name": config["certificate"]["secret_name"]
        if config["certificate"]["type"] == "existing"
        else None,
        **config.get("ingress", {}).get("terraform_overrides": {})
    }

This way terraform_overrides key can override any setting. Does this make sense?

[aktech]

This way terraform_overrides key can override any setting.

Yes, any variable present in the terraform. This makes more sense. I'll add this.