[aws-eks] reference a value returned through "kubectl get"

Provide a capability to reference values returned through kubectl get, then the value could be used by other parts of application later.

Example:

const hostname = new KubernetesGet(this, 'HostName', {
  kind: 'ingress',
  query: '$.items[0].status.loadBalancer.ingress.[0].hostname',
  wait: true // retry until the value becomes available
});

// then you can just reference the value like this:
hostname.valueAsString

Use Case

When orchestrating an application, the EKS cluster and resources created by k8s resource/helm chart are parts of the entire application.

For example, we deploy a helm chart with internal NLB/ALB ingress controller of a service. And the service exposed by EKS just is part of entire application(other services are be provided by ECS or EC2 auto scaling group).

We need the resource arn created by NLB/ALB ingress controller for entire application orchestration.

Proposed Solution

Other

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

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This is a 🚀 Feature Request

[eladb]

Okay, I think I understand the use case. Basically what you are looking for is a way to reference values returned from a kubectl get in your CDK app.

I think the main problem with this, in k8s, is that most of the apply operations are asynchronous. This means that you would need to “wait” for the resource to stabilize before we can issue the query, but I guess this query operation can also have some sort of retry support.

So perhaps something like this:

const hostname = new KubernetesGet(this, 'HostName', {
  kind: 'ingress',
  query: '$.items[0].status.loadBalancer.ingress.[0].hostname'
});

// then you can just reference the value like this:
hostname.valueAsString

[zxkane]

Okay, I think I understand the use case. Basically what you are looking for is a way to reference values returned from a kubectl get in your CDK app.

I think the main problem with this, in k8s, is that most of the apply operations are asynchronous. This means that you would need to “wait” for the resource to stabilize before we can issue the query, but I guess this query operation can also have some sort of retry support.

So perhaps something like this:

const hostname = new KubernetesGet(this, 'HostName', {
  kind: 'ingress',
  query: '$.items[0].status.loadBalancer.ingress.[0].hostname'
});

// then you can just reference the value like this:
hostname.valueAsString

It’s exactly what this feature requests. It could be a feature to verify the status of resources deployed via CDK.