kubernetes/kops · error

error finding default machine type

Error message

error finding default machine type: %v

What it means

defaultMachineType for AWS delegates to awsup.AWSCloud.DefaultInstanceType(cluster, ig), which probes the region for a suitable default instance type. This error wraps its failure when no default could be determined for the AWS cloud.

Solutions

1. Set spec.machineType explicitly on the InstanceGroup
2. Confirm the region supports the candidate defaults (try `aws ec2 describe-instance-type-offerings --region <region>`)
3. Check AWS credentials and EC2 API access from the machine running kOps
4. Upgrade kOps so defaults match current AWS offerings

Example fix

// before
kops create cluster ... --zones us-east-1a
// after
kops create cluster ... --zones us-east-1a --set spec.nodes.machineType=m5.large

// Ensure a machineType is set for AWS IGs to skip DefaultInstanceType entirely
if cluster.GetCloudProvider() == kops.CloudProviderAWS && ig.Spec.MachineType == "" {
    ig.Spec.MachineType = "t3.medium" // node default; use m5.large/c5.large for control-plane
}

When it happens

Trigger: PopulateInstanceGroupSpec (or NewCluster) with an empty machineType on AWS, where DefaultInstanceType fails — e.g. it can't validate candidate instance types against the region (EC2 API failure), or the IG role/bastion defaults are unavailable in the region.

Common situations: AWS regions where the built-in default candidates (e.g. t3.medium) aren't offered (opt-in regions); EC2 API credential/throttling problems; very old kOps defaults retired by AWS; control-plane defaults blocked by regional availability.

Related errors

• error assigning default machine type for nodes
• cannot parse VFS path
• could not find a suitable supported instance type for the…
• could not find public subnet in zone
• DNS ZoneID not set

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/2a5ac0259a505303. Report an issue: GitHub.

Appendix: source

Thrown at upup/pkg/fi/cloudup/populate_instancegroup_spec.go:336

		igKubeletConfig.AnonymousAuth = new(false)
	}

	ig.Spec.Kubelet = igKubeletConfig

	return ig, nil
}

// defaultMachineType returns the default MachineType for the instance group, based on the cloudprovider
func defaultMachineType(cloud fi.Cloud, cluster *kops.Cluster, ig *kops.InstanceGroup) (string, error) {
	switch cluster.GetCloudProvider() {
	case kops.CloudProviderAWS:
		if ig.Spec.Manager == kops.InstanceManagerKarpenter {
			return "", nil
		}

		instanceType, err := cloud.(awsup.AWSCloud).DefaultInstanceType(cluster, ig)
		if err != nil {
			return "", fmt.Errorf("error finding default machine type: %v", err)
		}
		return instanceType, nil

	case kops.CloudProviderGCE:
		switch {
		case ig.Spec.Role.HasControlPlane():
			return defaultMasterMachineTypeGCE, nil

		case ig.Spec.Role.HasNode():
			return defaultNodeMachineTypeGCE, nil

		case ig.Spec.Role.HasBastion():
			return defaultBastionMachineTypeGCE, nil
		}

	case kops.CloudProviderDO:
		switch {
		case ig.Spec.Role.HasControlPlane():

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