kubernetes/kops · error

error modifying volume

Error message

error modifying volume: %v

What it means

EC2 ModifyVolume failed while applying volume type/size/IOPS/throughput changes to an existing EBS master/etcd volume; AWS commonly rejects unsupported modifications (e.g. shrinking size, lowering IOPS below the type minimum, or unsupported type transitions).

Solutions

1. Ensure the new size is larger than the current size (EBS cannot shrink); migrate data to a new volume instead
2. Wait 6+ hours since the last modification if the AWS rate limit hit
3. Verify the volume type supports the requested throughput/IOPS
4. Grant ec2:ModifyVolume in the IAM policy

Example fix

// before
volumeSize: 10   // shrinking from 20 is unsupported
// after
volumeSize: 40   // only grow, or create a new volume and migrate

// Only ever grow volumes; check last-modification window
desc, _ := ec2Client.DescribeVolumes(ctx, &ec2.DescribeVolumesInput{VolumeIds: []string{volID}})
v := desc.Volumes[0]
if newSize < *v.Size { return errors.New("EBS volumes cannot be shrunk") }
if v.ModifiedAt != nil && time.Since(*v.ModifiedAt) < 6*time.Hour {
    return errors.New("volume modified <6h ago; AWS limits modification frequency")
}

When it happens

Trigger: ModifyVolume fails while reconciling changes to an existing volume — requesting a smaller size (shrink unsupported), invalid size/type/throughput combination, exceeding the 1000-modify-per-6h AWS limit per volume, missing ec2:ModifyVolume permission.

Common situations: Editing the instance group's volume size downward; changing throughput on a non-gp3 volume; re-running updates too frequently hitting the once-per-6-hours modification limit.

Related errors

• error adding AWS Tags to EBS Volume
• error creating PersistentVolume
• error deleting Volume
• error describing volumes
• error listing volumes

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/f0b0862cbaca81ae. Report an issue: GitHub.

Appendix: source

Thrown at upup/pkg/fi/cloudup/awstasks/ebsvolume.go:187

			}
		}

		if len(changes.VolumeType) > 0 ||
			changes.VolumeIops != nil ||
			changes.VolumeThroughput != nil ||
			changes.SizeGB != nil {

			request := &ec2.ModifyVolumeInput{
				VolumeId:   a.ID,
				VolumeType: e.VolumeType,
				Iops:       e.VolumeIops,
				Throughput: e.VolumeThroughput,
				Size:       e.SizeGB,
			}

			_, err := t.Cloud.EC2().ModifyVolume(ctx, request)
			if err != nil {
				return fmt.Errorf("error modifying volume: %v", err)
			}
		}
	}
	return nil
}

// getEBSVolumeTagsToDelete loops through the currently set tags and builds
// a list of tags to be deleted from the EBS Volume
func (e *EBSVolume) getEBSVolumeTagsToDelete(currentTags map[string]string) map[string]string {
	tagsToDelete := map[string]string{}
	for k, v := range currentTags {
		if _, ok := e.Tags[k]; !ok {
			tagsToDelete[k] = v
		}
	}

	return tagsToDelete
}

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