[Bug] [Regression] AMI type detection fails for non-"current generation" instances

[ConnorJC3]

What were you trying to accomplish?

Attempt to create a cluster using a node group with a non-amd64 instance type that is not marked in DescribeInstanceTypes as a "current generation" instance type. If this instance type needs a non-default AMI (such as, for example, it is an ARM instance), eksctl will not correctly choose the correct AMI and will instead default to the standard AMI.

What happened?

I tried to create a cluster using a node group with a1.large instances, to test support of the product I work on for this instance type. The latest version of ekctl failed to create the cluster, while older versions are able to.

How to reproduce it?

Attempt to create a cluster with a broken instance type. For this example, I am going to use an a1.large instance type, which is the first example in eksctl's ARM documentation:

$ eksctl create cluster --node-type=a1.large

2025-03-21 18:56:35 [ℹ]  eksctl version 0.205.0
...
2025-03-21 18:56:35 [ℹ]  nodegroup "ng-811a19e3" will use "" [AmazonLinux2/1.30]
...
2025-03-21 19:17:15 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:17:15 [!]  1 error(s) occurred and cluster hasn't been created properly, you may wish to check CloudFormation console
2025-03-21 19:17:15 [ℹ]  to cleanup resources, run 'eksctl delete cluster --region=us-west-2 --name=wonderful-creature-1742583949'
2025-03-21 19:17:15 [✖]  waiter state transitioned to Failure
Error: failed to create cluster "wonderful-creature-1742583949"

$ aws cloudformation describe-stack-events --stack-name eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3 | jq '.StackEvents[] | select(.ResourceStatus=="CREATE_FAILED") | .ResourceStatusReason'
"Resource handler returned message: \"[a1.large] is not a valid instance type for requested amiType AL2_x86_64 (Service: Eks, Status Code: 400, Request ID: 0a0b6cf0-930a-4c41-a2c1-00a2eb4370f1) (SDK Attempt Count: 1)\" (RequestToken: 2cca1041-5c10-6ca9-d11f-37255fb5f4f6, HandlerErrorCode: InvalidRequest)"

Logs

$ eksctl create cluster --node-type=a1.large
2025-03-21 19:05:49 [ℹ]  eksctl version 0.205.0
2025-03-21 19:05:49 [ℹ]  using region us-west-2
2025-03-21 19:05:50 [ℹ]  skipping us-west-2b from selection because it doesn't support the following instance type(s): a1.large
2025-03-21 19:05:50 [ℹ]  skipping us-west-2d from selection because it doesn't support the following instance type(s): a1.large
2025-03-21 19:05:50 [ℹ]  setting availability zones to [us-west-2a us-west-2c]
2025-03-21 19:05:50 [ℹ]  subnets for us-west-2a - public:192.168.0.0/19 private:192.168.64.0/19
2025-03-21 19:05:50 [ℹ]  subnets for us-west-2c - public:192.168.32.0/19 private:192.168.96.0/19
2025-03-21 19:05:50 [ℹ]  nodegroup "ng-811a19e3" will use "" [AmazonLinux2/1.30]
2025-03-21 19:05:50 [ℹ]  using Kubernetes version 1.30
2025-03-21 19:05:50 [ℹ]  creating EKS cluster "wonderful-creature-1742583949" in "us-west-2" region with managed nodes
2025-03-21 19:05:50 [ℹ]  will create 2 separate CloudFormation stacks for cluster itself and the initial managed nodegroup
2025-03-21 19:05:50 [ℹ]  if you encounter any issues, check CloudFormation console or try 'eksctl utils describe-stacks --region=us-west-2 --cluster=wonderful-creature-1742583949'
2025-03-21 19:05:50 [ℹ]  Kubernetes API endpoint access will use default of {publicAccess=true, privateAccess=false} for cluster "wonderful-creature-1742583949" in "us-west-2"
2025-03-21 19:05:50 [ℹ]  CloudWatch logging will not be enabled for cluster "wonderful-creature-1742583949" in "us-west-2"
2025-03-21 19:05:50 [ℹ]  you can enable it with 'eksctl utils update-cluster-logging --enable-types={SPECIFY-YOUR-LOG-TYPES-HERE (e.g. all)} --region=us-west-2 --cluster=wonderful-creature-1742583949'
2025-03-21 19:05:50 [ℹ]  default addons coredns, metrics-server, vpc-cni, kube-proxy were not specified, will install them as EKS addons
2025-03-21 19:05:50 [ℹ]  
2 sequential tasks: { create cluster control plane "wonderful-creature-1742583949", 
    2 sequential sub-tasks: { 
        2 sequential sub-tasks: { 
            1 task: { create addons },
            wait for control plane to become ready,
        },
        create managed nodegroup "ng-811a19e3",
    } 
}
2025-03-21 19:05:50 [ℹ]  building cluster stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:05:50 [ℹ]  deploying stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:06:20 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:06:51 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:07:51 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:08:51 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:09:51 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:10:52 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:11:52 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:12:52 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:13:53 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-cluster"
2025-03-21 19:13:54 [ℹ]  creating addon: coredns
2025-03-21 19:13:55 [ℹ]  successfully created addon: coredns
2025-03-21 19:13:55 [ℹ]  creating addon: metrics-server
2025-03-21 19:13:56 [ℹ]  successfully created addon: metrics-server
2025-03-21 19:13:56 [!]  recommended policies were found for "vpc-cni" addon, but since OIDC is disabled on the cluster, eksctl cannot configure the requested permissions; the recommended way to provide IAM permissions for "vpc-cni" addon is via pod identity associations; after addon creation is completed, add all recommended policies to the config file, under `addon.PodIdentityAssociations`, and run `eksctl update addon`
2025-03-21 19:13:56 [ℹ]  creating addon: vpc-cni
2025-03-21 19:13:56 [ℹ]  successfully created addon: vpc-cni
2025-03-21 19:13:57 [ℹ]  creating addon: kube-proxy
2025-03-21 19:13:57 [ℹ]  successfully created addon: kube-proxy
2025-03-21 19:15:59 [ℹ]  building managed nodegroup stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:15:59 [ℹ]  deploying stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:15:59 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:16:30 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:17:15 [ℹ]  waiting for CloudFormation stack "eksctl-wonderful-creature-1742583949-nodegroup-ng-811a19e3"
2025-03-21 19:17:15 [!]  1 error(s) occurred and cluster hasn't been created properly, you may wish to check CloudFormation console
2025-03-21 19:17:15 [ℹ]  to cleanup resources, run 'eksctl delete cluster --region=us-west-2 --name=wonderful-creature-1742583949'
2025-03-21 19:17:15 [✖]  waiter state transitioned to Failure
Error: failed to create cluster "wonderful-creature-1742583949"

Anything else we need to know?

N/A

Versions

$ eksctl info
eksctl version: 0.205.0
kubectl version: v1.32.2
OS: linux

[github-actions]

Hello ConnorJC3 👋 Thank you for opening an issue in eksctl project. The team will review the issue and aim to respond within 1-5 business days. Meanwhile, please read about the Contribution and Code of Conduct guidelines here. You can find out more information about eksctl on our website

[cheeseandcereal]

We changed the way we get instance info/parse instance types in #8206 by using the DescribeInstanceTypes API.

It looks like we excluded gathering instance info for non current-gen instances due to this filter:

eksctl/cmd/ec2geninfo/main.go

Line 118 in 2c879eb

{Name: aws.String("current-generation"), Values: []string{"true"}},

Doesn't seem like that filtering is helpful given we can support some non current-gen instances as you mention with the a1 instance family.