Importing .ova to EC2 fails with "ClientError: Unknown OS / Missing OS files."

Hi all,

I'm trying to convert VMware virtual machines to EC2 instances, but the import always fails with "ClientError: Unknown OS / Missing OS files."

Here's my process:

0. I start with a CentOS 7.9 VM on ESXi (supported according to https://docs.aws.amazon.com/vm-import/latest/userguide/vmie_prereqs.html#vmimport-operating-systems). The VM is bootable, has only one volume (MBR, ext4) and otherwise nothing special.

1. I use ovftools to export the VM from ESXi to .ova:

/usr/lib/vmware-ovftool/ovftool --X:logFile=mytestvm-log.txt --X:logLevel=warning --noSSLVerify --powerOffSource vi://$user:$pass@vmhost/mytestvm /volumes/vmexport/mytestvm.ova
Opening VI source: vi://$user@vmhost:443/mytestvm
Opening OVA target: /volumes/vmexport/mytestvm.ova
Writing OVA package: /volumes/vmexport/mytestvm.ova
Transfer Completed                    
Completed successfully

I tried this as well as exporting to OVF and then manually creating a tar file from it - same result. There's nothing in the log that indicates any problem. I can re-import the ova file and run it on ESXi, so it doesn't seem to be broken in any way.

2. Upload the .ova to S3:

aws s3 cp --sse --acl private /vm/mytestvm.ova s3://mv-ova-test

3. Create a presigned URL for the file:

aws s3  presign s3://mv-ova-test/mytestvm.ova --expires-in 86400

4. Make a .json to describe the import:

[
  {
    "Description": "ova-import-test",
    "Format": "ova",
    "Url": "https://mv-ova-test.s3.eu-central-1.amazonaws.com/mytestvm.ova?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential={the rest of the URL}"
  }
]

5. Start the import:

aws ec2 import-image --description "ova import test" --disk-containers "file://mytestvm.json"

{
    "Description": "test ova import",
    "ImportTaskId": "import-ami-06c5fc120d02749d7",
    "Progress": "1",
    "SnapshotDetails": [
        {
            "Description": "mytestvm",
            "DiskImageSize": 0.0,
            "Format": "OVA",
            "Url": "https://mv-ova-test.s3.eu-central-1.amazonaws.com/mytestvm.ova?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential={the rest of the URL}",
            "UserBucket": {}
        }
    ],
    "Status": "active",
    "StatusMessage": "pending"
}

6. Check the import task:

{
    "ImportImageTasks": [
       
            "Description": "test ova import",
            "ImportTaskId": "import-ami-06c5fc120d02749d7",
            "Progress": "19",
            "SnapshotDetails": [
                {
                    "DiskImageSize": 7062419968.0,
                    "Format": "VMDK",
                    "Status": "active",
                    "Url": "https://mv-ova-test.s3.eu-central-1.amazonaws.com/mytestvm.ova?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential={the rest of the URL}",
                    "UserBucket": {}
                }
            ],
            "Status": "active",
            "StatusMessage": "converting",
            "Tags": []
        }
    ]
}

7. And in the end I get:

{
    "ImportImageTasks": [
        {
            "Description": "test ova import",
            "ImportTaskId": "import-ami-06c5fc120d02749d7",
            "SnapshotDetails": [
                {
                    "DeviceName": "/dev/sde",
                    "DiskImageSize": 7062419968.0,
                    "Format": "VMDK",
                    "Status": "completed",
                    "Url": "https://mv-ova-test.s3.eu-central-1.amazonaws.com/mytestvm.ova?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential={the rest of the URL}",
                    "UserBucket": {}
                }
            ],
            "Status": "deleted",
            "StatusMessage": "ClientError: Unknown OS / Missing OS files.",
            "Tags": []
        }
    ]
}

8. Trying to import the vmdk alone makes no difference:

{
    "ImportImageTasks": [
        {
            "Description": "test vmdk import",
            "ImportTaskId": "import-ami-0e1dc2522176e0cdf",
            "SnapshotDetails": [
                {
                    "Description": "test-vm",
                    "DeviceName": "/dev/sde",
                    "DiskImageSize": 7062419968.0,
                    "Format": "VMDK",
                    "Status": "completed",
                    "Url": "https://mv-ova-test.s3.eu-central-1.amazonaws.com/mytestvm.ova?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential={the rest of the URL}",
                    "UserBucket": {}
                }
            ],
            "Status": "deleted",
            "StatusMessage": "ClientError: Unknown OS / Missing OS files.",
            "Tags": []
        }
    ]
}

So. What could be the cause for "ClientError: Unknown OS / Missing OS files" if I use a supported OS and the .ova seems to be intact? Would I have the same issue if I tried using MGN for this?

Thanks,

Marc