omitting instanceType with instancesDistribution causes it to pick m5.large

[mdaniel]

What happened?

If one omits instanceType: which is permissible, eksctl will insert m5.large even though the instanceTypes: do not contain any m5

This causes two bad things: misleading nodegroup output:

$ eksctl get nodegroups --cluster eks0
eks0	p2-xl		2019-06-05T18:30:09Z	1		16		1			m5.large	ami-0923e4b35a30a5f53

and, related to #844, it acts as if the nodegroup is composed of m5.large and thus throws off the GPU AMI detection:

2019-06-05T17:39:11-07:00 [▶]  resolving AMI using StaticGPUResolver for region us-west-2, instanceType m5.large and imageFamily AmazonLinux2
2019-06-05T17:39:11-07:00 [▶]  can't resolve AMI using StaticGPUResolver as instance type m5.large is non-GPU
2019-06-05T17:39:11-07:00 [▶]  resolving AMI using StaticDefaultResolver for region us-west-2, version 1.12, instanceType m5.large and imageFamily AmazonLinux2
2019-06-05T17:39:11-07:00 [ℹ]  nodegroup "p2-xl" will use "ami-0923e4b35a30a5f53" [AmazonLinux2/1.12]

What you expected to happen?

It should treat instanceType: as being mixed, the only other supported value when using instancesDistribution

How to reproduce it?

nodeGroups:
- name: p2-xl
  desiredCapacity: 1
  instancesDistribution:
    instanceTypes:
    - p2.xlarge
    - p2.8xlarge
    - p2.16xlarge
    maxPrice: 0.50

$ eksctl create nodegroup --config-file foo.yml

Anything else we need to know?

• macOS
• brew install weaveworks/tap/eksctl
• ~/.aws/config with an MFA

Versions
Please paste in the output of these commands:

$ eksctl version
[ℹ]  version.Info{BuiltAt:"", GitCommit:"", GitTag:"0.1.34"}
$ uname -a
Darwin mdaniel.local 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64
$ kubectl version
Client Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.2", GitCommit:"66049e3b21efe110454d67df4fa62b08ea79a19b", GitTreeState:"clean", BuildDate:"2019-05-21T23:03:55Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"12+", GitVersion:"v1.12.6-eks-d69f1b", GitCommit:"d69f1bf3669bf00b7f4a758e978e0e7a1e3a68f7", GitTreeState:"clean", BuildDate:"2019-02-28T20:26:10Z", GoVersion:"go1.10.8", Compiler:"gc", Platform:"linux/amd64"}

Logs

2019-06-05T17:39:09-07:00 [ℹ]  using region us-west-2
2019-06-05T17:39:10-07:00 [▶]  cluster = {
  Arn: "arn:aws:eks:us-west-2:XXXXXXXXXXXX:cluster/eks0",
  CertificateAuthority: {
    Data: "LS0tLS:snip:="
  },
  CreatedAt: 2019-06-05 18:18:58 +0000 UTC,
  Endpoint: "https://example.com",
  Logging: {
    ClusterLogging: [{
        Enabled: false,
        Types: [
          "api",
          "audit",
          "authenticator",
          "controllerManager",
          "scheduler"
        ]
      }]
  },
  Name: "eks0",
  PlatformVersion: "eks.2",
  ResourcesVpcConfig: {
    EndpointPrivateAccess: false,
    EndpointPublicAccess: true,
    SecurityGroupIds: ["sg-00810e48d599e0036"],
    SubnetIds: [
      "subnet-04b2b23d69608ab3a",
      "subnet-0a38d42ee58643879",
      "subnet-0c1865407f313bed4",
      "subnet-08db182c4d36813ab",
      "subnet-09efa7a5a407a81b0",
      "subnet-019756b4261d1276a",
      "subnet-0ef1ee611663c1aef",
      "subnet-0f40edff1302cb28c"
    ],
    VpcId: "vpc-0967356bc85cdb80e"
  },
  RoleArn: "arn:aws:iam::XXXXXXXXXXXX:role/eksctl-eks0-cluster-ServiceRole-QLAEZCL767W3",
  Status: "ACTIVE",
  Version: "1.12"
}
2019-06-05T17:39:10-07:00 [ℹ]  will use version 1.12 for new nodegroup(s) based on control plane version
2019-06-05T17:39:11-07:00 [▶]  nodegroups = []
2019-06-05T17:39:11-07:00 [▶]  resolving AMI using StaticGPUResolver for region us-west-2, instanceType m5.large and imageFamily AmazonLinux2
2019-06-05T17:39:11-07:00 [▶]  can't resolve AMI using StaticGPUResolver as instance type m5.large is non-GPU
2019-06-05T17:39:11-07:00 [▶]  resolving AMI using StaticDefaultResolver for region us-west-2, version 1.12, instanceType m5.large and imageFamily AmazonLinux2
2019-06-05T17:39:11-07:00 [ℹ]  nodegroup "p2-xl" will use "ami-0923e4b35a30a5f53" [AmazonLinux2/1.12]

[martina-if]

Hi @mdaniel, thank you for the detailed report! I see we have a bug there. I am looking into this now.