kubernetes/kops · error

error detaching instance %q: %v

Error message

error detaching instance %q: %v

What it means

The subsequent DetachInstances call failed while removing the instance from its autoscaling group during rolling update; commonly the ASG name is stale (already deleted) or AWS rejects the detach because the instance is already detached.

Source

Thrown at upup/pkg/fi/cloudup/awsup/aws_cloud.go:696

	if id == "" {
		return fmt.Errorf("id was not set on CloudInstance: %v", i)
	}

	asg := i.CloudInstanceGroup.Raw.(*autoscalingtypes.AutoScalingGroup)
	if err := c.CreateTags(id, map[string]string{tagNameDetachedInstance: *asg.AutoScalingGroupName}); err != nil {
		return fmt.Errorf("error tagging instance %q: %v", id, err)
	}

	// TODO this also deregisters the instance from any ELB attached to the ASG. Do we care?

	input := &autoscaling.DetachInstancesInput{
		AutoScalingGroupName:           aws.String(i.CloudInstanceGroup.HumanName),
		InstanceIds:                    []string{id},
		ShouldDecrementDesiredCapacity: aws.Bool(false),
	}

	if _, err := c.Autoscaling().DetachInstances(ctx, input); err != nil {
		return fmt.Errorf("error detaching instance %q: %v", id, err)
	}

	klog.V(8).Infof("detached aws ec2 instance %q", id)

	return nil
}

// GetCloudGroups returns a groups of instances that back a kops instance groups
func (c *awsCloudImplementation) GetCloudGroups(cluster *kops.Cluster, instancegroups []*kops.InstanceGroup, warnUnmatched bool, nodes []v1.Node) (map[string]*cloudinstances.CloudInstanceGroup, error) {
	ctx := context.TODO()

	if c.spotinst != nil {
		sgroups, err := spotinst.GetCloudGroups(c.spotinst, cluster, instancegroups, warnUnmatched, nodes)
		if err != nil {
			return nil, err
		}

		if featureflag.SpotinstHybrid.Enabled() {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Verify the ASG still exists and contains the instance
2. Re-run the rolling update; concurrent detachment can cause this transiently
3. Check autoscaling:DetachInstances permissions

When it happens

Trigger: Thrown at upup/pkg/fi/cloudup/awsup/aws_cloud.go:696 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/d1359f36318e68f9. Report an issue: GitHub.