# Resize an instance

You can change the size of an instance by changing its flavor. This rebuilds the instance and therefore results in a restart.

To list the VMs you want to resize, run:

    $ openstack server list

Once you have the name or UUID of the server you wish to resize, resize it using the openstack server resize command:

    $ openstack server resize --flavor FLAVOR SERVER

Note

By default, the openstack server resize command gives the guest operating system a chance to perform a controlled shutdown before the instance is powered off and the instance is resized. This behavior can be configured by the administrator but it can also be overridden on a per image basis using the `os_shutdown_timeout` image metadata setting. This allows different types of operating systems to specify how much time they need to shut down cleanly. See Useful image properties for details.

Resizing can take some time. During this time, the instance status will be `RESIZE`:

    $ openstack server list
    +----------------------+----------------+--------+-----------------------------------------+
    | ID                   | Name           | Status | Networks                                |
    +----------------------+----------------+--------+-----------------------------------------+
    | 67bc9a9a-5928-47c... | myCirrosServer | RESIZE | admin_internal_net=192.168.111.139      |
    +----------------------+----------------+--------+-----------------------------------------+

When the resize completes, the instance status will be `VERIFY_RESIZE`. You can now confirm the resize to change the status to `ACTIVE`:

    $ openstack server resize confirm SERVER

Note

The resized server may be automatically confirmed based on the administrator’s configuration of the deployment.

If the resize does not work as expected, you can revert the resize. This will revert the instance to the old flavor and change the status to `ACTIVE`:

    $ openstack server resize revert SERVER

this page last updated: 2026-04-14 07:16:25

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