WIP: Nodegroup as a resource

[richardcase]

Description

This is WIP for adding the following:

• eksctl get nodegroup
• eksctl create nodegroup
• eksctl delete nodegroup

Tasks to complete

• Create get command
• Test get command
• Create create command
• Test create command
• Create delete command
• Test delete command
• Update delete cluster command
• Update scale nodegroup command
• Add support for node labels
• Add integration tests to cover nodegroup lifecycle
• Update documentation

Checklist

• Code compiles correctly (i.e make build)
• Added tests that cover your change (if possible)
• All tests passing (i.e. make test)
• Added/modified documentation as required (such as the README)
• Added yourself to the humans.txt file

[errordeveloper]

@richardcase #293 is probably relevant for creation, especially in the context of #232; but neither have to be required for initial implementation (we can fix such limitations separately, if solution is not obvious).

[errordeveloper]

Yes, this would be needed (see #232). When unspecified it'd be inherited from the cluster stack.

[richardcase]

@errordeveloper - i'm still working on this. Taking me a little longer than i ever anticipated due to starting a new job.

[mumoshu]

@richardcase Hey! Can I take this?

// Btw, thanks for your awesome work ☺️

[richardcase]

Hi @mumoshu - that would be great if you could take it, thanks a lot 👍 I've started a new job and struggling with time.

Do you want to work against this branch/pr or would you like to start clean?

[mumoshu]

@richardcase Thanks for the response!

I'd rather keep this PR as-is for reference. But I do want to write a big credit/acknowledgement on your work in my PR.

Would it sounds ok to you?

[mumoshu]

@richardcase This seems to result in CreateNodeGroups trying to create all the stacks for all the node groups, not only the stack for the specified node gorup ng *api.NodeGroup.

So, shouldn't we change this to work against the single node group per each create nodegroup command?

[mumoshu]

Probably the code would look something like err := stackManager.CreateNodeGroup(ng)

[mumoshu]

This breaks after you create a nodegroup and then delete it. We'd better use a semi-random name other than an auto-incremented index. UUID can be used for example, but I'd use the same fancy names used for cluster names.

---

Let's say you had firstly created a nodegroup with ID=0(=maxSeq + 1), the subsequent create nodegroup sees maxSeq as 1! Which breaks assumptions in the codebase and results in index out of bound errors.

This happens because CloudFormation DescribeStacks API returns stacks in DELETE_COMPLETE for a while(maybe several to dozen minutes). See the StackStatus: "DELETE_COMPLETE", part of the example API response below:

2018-12-04T17:05:59+09:00 [▶]  stacks = [{
  Capabilities: ["CAPABILITY_IAM"],
  CreationTime: 2018-12-04 07:21:34.572 +0000 UTC,
  DeletionTime: 2018-12-04 07:49:49.204 +0000 UTC,
  Description: "EKS nodes (AMI family: AmazonLinux2, SSH access: false, subnet topology: Public) [created and managed by eksctl]",
  DisableRollback: false,
  Outputs: [{
      ExportName: "eksctl-adorable-sheepdog-1543570021-nodegroup-0::InstanceRoleARN",
      OutputKey: "InstanceRoleARN",
      OutputValue: "arn:aws:iam::ACCOUNT:role/eksctl-adorable-sheepdog-15435700-NodeInstanceRole-9D8J0JPOZOA"
    }],
  RollbackConfiguration: {

  },
  StackId: "arn:aws:cloudformation:us-west-2:ACCOUNT:stack/eksctl-adorable-sheepdog-1543570021-nodegroup-0/3aed7b30-f795-11e8-99dc-500c337110fd",
  StackName: "eksctl-adorable-sheepdog-1543570021-nodegroup-0",
  StackStatus: "DELETE_COMPLETE",
  Tags: [{
      Key: "eksctl.cluster.k8s.io/v1alpha1/cluster-name",
      Value: "adorable-sheepdog-1543570021"
    },{
      Key: "eksctl.cluster.k8s.io/v1alpha1/nodegroup-id",
      Value: "0"
    }]
}]

[mumoshu]

Update: So I was able to fix the index out of bound errors just by replacing a bunch of ng.ID that are used to drill down ClusterConfig to a single node group inside it, to use api.NodeGroup instead.

I'll keep it going with ng.ID = maxSeq + 1 for now.