# VM Creation Failed Due to Port Binding Failure

## Problem <a href="#problem" id="problem"></a>

VM creation failed due to the following error:

{% code title="ostackhost.logs" %}

```bash
nova.exception.PortBindingFailed: Binding failed for port [PORT-UUID] please check neutron logs for more information.
```

{% endcode %}

## Environment

* Private Cloud Director Virtualization - v2025.4 and Higher
* Private Cloud Director Kubernetes – v2025.4 and Higher
* Self-Hosted Private Cloud Director Virtualization - v2025.4 and Higher
* Self-Hosted Private Cloud Director Kubernetes - v2025.4 and Higher
* Component: Networking Service

## Cause <a href="#cause" id="cause"></a>

This issue occurs when Neutron agents on compute nodes are unable to bind the requested port to the VM. Common causes include:

* OVN controller on the compute node is unresponsive or out of sync with the OVN Southbound database.
* Neutron server-to-OVN database communication issues.
* Stale port binding records in OVN or Neutron.

## Diagnostics <a href="#diagnostics" id="diagnostics"></a>

* Review ostackhost logs on the affected compute host:

  ```bash
  $ cat /var/log/pf9/ostackhost.log | grep -i <VM_ID>
  ```
* Check Neutron agent status:

  ```bash
  $ openstack network agent list
  ```
* Review OVN controller logs on the compute node:

  ```bash
  $ sudo journalctl -u ovn-controller -f
  $ cat /var/log/ovn/ovn-controller.log
  ```

## Resolution <a href="#resolution" id="resolution"></a>

Restart OVN services on the affected compute node(s):

```bash
$ sudo systemctl restart ovn-controller
```

{% hint style="warning" %}
Restarting `ovn-controller` on a compute node generally does not disrupt existing VM traffic since OVS flows remain programmed, but it temporarily prevents new port bindings, VM spawns, or security group updates
{% endhint %}

## Validation <a href="#validation" id="validation"></a>

* Confirm the VM builds successfully
* Verify the Neutron port binding:

  ```bash
  $ openstack port list --server <vm-id>
  ```


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