> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmo/how-to/instance-migration-fails-with-error-not-able-to-execute-ssh-com.md).

# Instance Migration Fails With Error "not able to execute ssh command: Unexpected error while running command.

## Problem

Instance migration fails with the following erroron the source host.

{% tabs %}
{% tab title="None" %}

```none
973 INFO nova.compute.manager [req-[rUUID] admin@platform9.net admin] [instance: [UUID]] Setting instance back to ACTIVE after: Instance rollback performed due to: Resize error: not able to execute ssh command: Unexpected error while running command.Command: ssh -o BatchMode=yes A.B.C.D mkdir -p /pf9/instances/[UUID]Exit code: 255Stdout: u''Stderr: u"Warning: Permanently added 'A.B.C.D' (ECDSA) to the list of known hosts.\r<br>Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).\r<br>"
```

{% endtab %}
{% endtabs %}

## Environment

Platform9 Managed OpenStack - v3.6.0 and Higher

## Cause

Password-less authentication is not configured between source and destination hosts.

## Resolution

Set up password-less authentication between the current host and the new host as OpenStack requires a password-less authentication to copy the instance and the associated files to the destination host.


---

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