# Reboot an Instance

## Problem

User has the need to reboot an instance.

## Environment

* Platform9 Managed OpenStack - All Versions
* Nova

## Procedure

1. By default, when an instance is rebooted, it is a soft reboot. A soft reboot attempts a graceful shutdown and restart of the instance.

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

```none
$ openstack server reboot SERVER
```

{% endtab %}
{% endtabs %}

2. To perform a hard reboot, pass the \*\*`--hard`\*\*parameter. A hard reboot power cycles the instance.

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

```none
$ openstack server reboot --hard SERVER
```

{% endtab %}
{% endtabs %}

3. Rescue mode provides a way for access, even if an image renders the instance inaccessible. By default, it starts an instance from the initial image attaching the current boot disk as a secondary one. For example, this operation may be performed, if a filesystem of an instance becomes corrupted due to prolonged use.
   1. To perform an instance reboot into rescue mode, run the following command.

```
$ openstack server rescue SERVER
```

```
2. To restart the instance from the normal boot disk, run the following command.
```

```
$ openstack server unrescue SERVER
```

```
3. If you want to rescue an instance with a specific image, rather than the default one, use the **`--image`** parameter.
```

```
$ nova rescue --image IMAGE_ID SERVER
```

**Note:** On running the \*\*`--openstack server rescue`\*\*command, the instance performs a soft shutdown first. This means that the guest operating system has a chance to perform a controlled shutdown before the instance is powered off. The shutdown behavior is configured by the \*\*`shutdown_timeout`\*\*parameter that can be set in the *nova.conf* file. Its value stands for the overall period (in seconds) a guest operating system is allowed to complete the shutdown. The default timeout is 60 seconds. The timeout value can be overridden on a per image basis by means of \*\*`os_shutdown_timeout`\*\*that is an image metadata setting allowing different types of operating systems to specify how much time they need to shut down cleanly.

## Additional Information

[Reboot an Instance](https://docs.openstack.org/ocata/user-guide/cli-reboot-an-instance.html)


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