# VM Network Port Attachment Failure and High CPU Usage on OVNDB

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

PCD environment is experiencing a critical failure in VM network port attachment operations, preventing virtual machines from connecting to the network. The service is consuming 88-95% CPU, causing it to become unavailable for legitimate API requests.

{% code title="OVN Logs" %}

```
|poll_loop|INFO|Dropped 79 log messages in last 94 seconds (most recently, 91 seconds ago) due to excessive rate
|poll_loop|INFO|wakeup due to 0-ms timeout at ../ovsdb/jsonrpc-server.c:616 (95% CPU usage)
```

{% endcode %}

{% code title="ostackhost Logs" %}

```
nova.exception.PortInUse: Port <PORT_UUID> is still in use.
```

{% endcode %}

### Environment <a href="#environment" id="environment"></a>

* 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

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

The OVN Database (OVN-DB) service has entered a non-responsive state characterised by a high-CPU spin loop.

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

{% hint style="info" %}
Step 2 -3 only accessible and applicable for the Self-Hosted Private Cloud Director.&#x20;

For SaaS environments, please reach out to Platform9 support.
{% endhint %}

1. VM deployment fails with the below exception shown on the `pf9-ostackhost` logs located on the hypervisor at location `/var/log/pf9/`.

   <pre data-title="ostackhost Logs"><code>nova.exception.PortInUse: Port &#x3C;PORT_UUID> is still in use.
   </code></pre>
2. Review the `ovn-ovsdb-sb-0` pod logs from the workload region namespace.

   ```
   $ kubectl logs -n <WORKLOAD_NAMESPACE> <OVN_OVSDB_POD_NAME>
   ```
3. Validate the above pod logs and check CPU usage messages like those shown in the below snippet.

   ```
   |poll_loop|INFO|wakeup due to 0-ms timeout at ../ovsdb/jsonrpc-server.c:616 (95% CPU usage)
   ```

## Resolution

{% hint style="info" %}
Only accessible and applicable for the Self-Hosted Private Cloud Director.&#x20;

For SaaS environments, please reach out to Platform9 support.
{% endhint %}

1. Take the backup of OVNDB database.

   ```
   $ kubectl cp <WORKLOAD_NAMESPACE>/<OVN_OVSDB_NB_POD_NAME>:/var/lib/ovn/ovnnb_db.db  ./ovnnb_db_backup.db
   $ kubectl cp <WORKLOAD_NAMESPACE>/<OVN_OVSDB_SB_POD_NAME>:/var/lib/ovn/ovnsb_db.db ./ovnsb_db_backup.db
   ```
2. Once backup is taken, execute compaction command

   ```
   $ kubectl exec <OVN_OVSDB_NB_POD_NAME> -n <WORKLOAD_NAMESPACE> -- ovn-appctl -t /var/run/ovn/ovnnb_db.ctl ovsdb-server/compact
   $ kubectl exec <OVN_OVSDB_SB_POD_NAME> -n <WORKLOAD_NAMESPACE> -- ovn-appctl -t /var/run/ovn/ovnsb_db.ctl ovsdb-server/compact
   ```
3. Enable memory compaction on the below pods

   ```
   $ kubectl exec <OVN_OVSDB_NB_POD_NAME> -n <WORKLOAD_NAMESPACE> -- \
     ovn-appctl -t /var/run/ovn/ovnnb_db.ctl ovsdb-server/memory-trim-on-compaction on

   $ kubectl exec <OVN_OVSDB_SB_POD_NAME> -n <WORKLOAD_NAMESPACE> -- \
     ovn-appctl -t /var/run/ovn/ovnsb_db.ctl ovsdb-server/memory-trim-on-compaction on
   ```
4. Restart the below pods

   ```
   $ kubectl delete <OVN_OVSDB_NB_POD_NAME> -n <WORKLOAD_NAMESPACE>
   $ kubectl delete <OVN_OVSDB_SB_POD_NAME> -n <WORKLOAD_NAMESPACE>
   ```

## Validation

{% hint style="info" %}
Step 1-2 is applicable for the Self-Hosted Private Cloud Director.&#x20;

For SaaS environments, please reach out to Platform9 support.
{% endhint %}

1. Check the pods' status; it should be running

   ```
   $ kubectl get pods -n <WORKLOAD_NAMESPACE>  | grep -i ovn
   ```
2. Review the `ovn-ovsdb` pod logs from the workload region namespace and confirm if no high CPU usage messages are logged in these pods.

   ```
   $ kubectl logs -n <WORKLOAD_NAMESPACE> <OVN_OVSDB_POD_NAME>
   ```
3. Deploy a new VM and review the `pf9-ostackhost` logs from the hypervisor (host); it no longer logs `Port <PORT_UUID> is still in use` messages.


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