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.

None

$ openstack server reboot SERVER

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

None

$ openstack server reboot --hard SERVER

1. 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