Use snapshots to migrate instances¶

Create a snapshot of the instance¶

1. Shut down the source VM before you take the snapshot to ensure that all data is flushed to disk. If necessary, list the instances to view the instance name:

   $ openstack server list
   +--------------------------------------+------------+--------+------------------+--------------------+-------------------------+
   | ID                                   | Name       | Status | Networks         | Image              | Flavor                  |
   +--------------------------------------+------------+--------+------------------+--------------------+-------------------------+
   | d0d1b7d9-a6a5-41d3-96ab-07975aadd7fb | myInstance | ACTIVE | private=10.0.0.3 | ubuntu-16.04-amd64 | general.micro.tmp.linux |
   +--------------------------------------+------------+--------+------------------+--------------------+-------------------------+
   

2. Use the openstack server stop command to shut down the instance:

   $ openstack server stop myInstance
   

3. Use the openstack server list command to confirm that the instance shows a SHUTOFF status:

   $ openstack server list
   +--------------------------------------+------------+---------+------------------+--------------------+-------------------------+
   | ID                                   | Name       | Status  | Networks         | Image              | Flavor                  |
   +--------------------------------------+------------+---------+------------------+--------------------+-------------------------+
   | d0d1b7d9-a6a5-41d3-96ab-07975aadd7fb | myInstance | SHUTOFF | private=10.0.0.3 | ubuntu-16.04-amd64 | general.micro.tmp.linux |
   +--------------------------------------+------------+---------+------------------+--------------------+-------------------------+
   

4. Use the openstack server image create command to take a snapshot:

   $ openstack server image create --name myInstanceSnapshot myInstance
   

   If snapshot operations routinely fail because the user token times out while uploading a large disk image, consider configuring nova to use service user tokens.

5. Use the openstack image list command to check the status until the status is ACTIVE:

   $ openstack image list
   +--------------------------------------+---------------------------+--------+
   | ID                                   | Name                      | Status |
   +--------------------------------------+---------------------------+--------+
   | ab567a44-b670-4d22-8ead-80050dfcd280 | myInstanceSnapshot        | active |
   +--------------------------------------+---------------------------+--------+
   

Download the snapshot as an image¶

1. Get the image ID:

   $ openstack image list
   +--------------------------------------+---------------------------+--------+
   | ID                                   | Name                      | Status |
   +--------------------------------------+---------------------------+--------+
   | ab567a44-b670-4d22-8ead-80050dfcd280 | myInstanceSnapshot        | active |
   +--------------------------------------+---------------------------+--------+
   

2. Download the snapshot by using the image ID that was returned in the previous step:

   $ openstack image save --file snapshot.raw ab567a44-b670-4d22-8ead-80050dfcd280
   

   Note

   The openstack image save command requires the image ID and cannot use the image name. Check there is sufficient space on the destination file system for the image file.

3. Make the image available to the new environment, either through HTTP or direct upload to a machine (scp).

Import the snapshot to the new environment¶

In the new project or cloud environment, import the snapshot:

$ openstack image create --container-format bare --disk-format qcow2 \
  --file snapshot.raw myInstanceSnapshot

Boot a new instance from the snapshot¶

In the new project or cloud environment, use the snapshot to create the new instance:

$ openstack server create --flavor m1.tiny --image myInstanceSnapshot myNewInstance