Create and manage snapshots

You can create a snapshot from an instance, either as a backup, or to use it as the source image when creating new instances. Either way, there are a couple of things to consider before creating the snapshot:

• Does the instance have one or more volumes attached? If so, you may need to comment out mounts from /etc/fstab first, to ensure that new instances are able to boot without failures, if using the snapshot as a source image for new instances.

• In order to ensure consistency when using the snapshot as a source image for new instances, it is always best to shut down the instance before taking a snapshot of it.

Create

Follow these steps to create a snapshot of an instance.

Dashboard

1. In the dashboard, select Instances in the Compute tab:

   

2. Use the drop-down menu and select Shut off instance:

   

3. When the instance is shut off, use the drop-down menu and select Create Snapshot:

   

4. Fill in the Snapshot Name and click on Create Snapshot in the window that appears:

   

The snapshot is now created, and will be located under Images in the Compute tab. The image list will be long, use the search field to enter part of the name of your image and it should appear:

Note

Image creation may take a long time. You may need to reload the browser page.

CLI

1. First list your instances (servers):

   $ openstack server list
   +--------------------------------------+--------+--------+----------------------------------------+---------------+----------+
   | ID                                   | Name   | Status | Networks                               | Image         | Flavor   |
   +--------------------------------------+--------+--------+----------------------------------------+---------------+----------+
   | fd35e22f-6519-46d5-95c1-01e80b02ca17 | test01 | ACTIVE | IPv6=2001:700:2:8201::1246, 10.2.2.105 | GOLD CentOS 8 | m1.small |
   +--------------------------------------+--------+--------+----------------------------------------+---------------+----------+
   

2. Shut off the server for which you want a snapshot (this can be omitted at the risk of compromising the integrity of the OS within the snapshot):

   $ openstack server stop fd35e22f-6519-46d5-95c1-01e80b02ca17
   

3. Take a snapshot:

   $ openstack server image create --name test01-snapshot fd35e22f-6519-46d5-95c1-01e80b02ca17
   (output omitted...)
   

4. Turn on the server (optional):

   $ openstack server start fd35e22f-6519-46d5-95c1-01e80b02ca17
   

5. List images to verify that your snapshot has been created (optional):

   $ openstack image list --private
   +--------------------------------------+-----------------+--------+
   | ID                                   | Name            | Status |
   +--------------------------------------+-----------------+--------+
   | 6edb8ab8-df9b-4339-b5d0-9e33d9d36e5d | my-test-image   | active |
   | 8fae2165-ef86-4e36-91a5-5caad9698aab | test01-snapshot | active |
   +--------------------------------------+-----------------+--------+
   

Download

There are valid reasons to download the snapshot to a local computer. One reason would be to have an off-site backup of the instance. Another is to upload the snapshot to another project in order to use it as a source image for instances in that project.

Downloading a snapshot is not possible via the dashboard, it is only possible via the CLI or API. The steps needed to download the snapshot via CLI are detailed below.

CLI

1. List images using the option --private, thus excluding official NREC images:

   $ openstack image list --private
   +--------------------------------------+-----------------+--------+
   | ID                                   | Name            | Status |
   +--------------------------------------+-----------------+--------+
   | ada4524b-72f5-4b41-b28e-1ac57c6634a0 | test01-snapshot | active |
   +--------------------------------------+-----------------+--------+
   

2. Download the image using the image ID. Select a name of the file (here: test01-snapshot.img) for the --file option:

   $ openstack image save --file test01-snapshot.img ada4524b-72f5-4b41-b28e-1ac57c6634a0
   $ ls -lh test01-snapshot.img
   -rw-r--r--. 1 user group 10G Feb 11 14:18 test01-snapshot.img
   

Upload

If you have previously downloaded a snapshot as described in Downloading a snapshot, you can upload it to a different project or region. An snapshot is uploaded as an image.

Note

The uploaded snapshot image will not have the same properties as the original image prior to snapshot and download. This may cause problems. One such problem is changed network interface card name for Debian instance. To solve this problem, you need to manually set the original properties to the uploaded snapshot image, as described in troubleshooting. General useful image properties are described in Upload and manage images. Please also check out Frequently Asked Questions (FAQ).

Dashboard

In order to upload a snapshot, navigate to Images and click on Create Image:

In the window that appears, you have to specify a name for the image (here: “my-test-image”), select the file on your computer (here: “test01-snapshot.img”) and select the image format. In our case, and for previously downloaded snapshots, the image format is “Raw”:

You can also set an optional description, and metadata info such as disk and memory requirements. Click on “Create Image” to proceed. Note that images and snapshots are large files and uploading may take a very long time.

After the image has been uploaded, it will appear in the Images tab:

CLI

Note

If the purpose of uploading the snapshot is to move a workload or instance between projects, make sure that your shell environment variables are set correctly:

$ env | egrep '(OS_REGION_NAME|OS_PROJECT_NAME)'
OS_REGION_NAME=osl
OS_PROJECT_NAME=DEMO-xxxxxxxx.uio.no

Change these variables according to which project and region where you want to upload the snapshot, e.g.:

$ export OS_PROJECT_NAME=PRIVATE-xxxxxxxx.uio.no

Upload the image with:

$ openstack image create --file test01-snapshot.img --disk-format raw my-test-image
(output omitted)

You need to specify the file name, disk format and a name for the image. Other metadata for the image may be set with additional options, se the output of openstack image create --help for more information.

Launch

Dashboard: Directly from snapshot image

Select Images in the Compute tab:

Choose the snapshot, and click on Launch, and further steps are described under create virtual machine.

The new instance contains now the expected customizations made earlier in your previous instance.

Dashboard: By creating instance

Follow the steps outlined in Create a Linux virtual machine. The only difference is when choosing the image from which to launch the new instance. Choose Instance Snapshot as the boot source and your snapshots should appear. Then choose the preferred snapshot and proceed as normal:

You can also launch an instance from the Images tab. Choose the snapshot, and click on Launch, and further steps are described under Create a Linux virtual machine.

The new instance contains now the expected customizations made earlier in your previous instance.

CLI

This will be exactly as described in Create a Linux virtual machine. Use your snapshot as the source for the instance:

$ openstack server create --image "test01-snapshot" --flavor m1.small \
      --security-group SSH_and_ICMP --security-group default \
      --key-name mykey --nic net-id=IPv6 myserver

Delete

Note

You can not delete a snapshot that is being used as a source image for an instance. If you try to delete a snapshot that is in use as a source image, you will get an error:

In order to delete a snapshot that no longer need, follow these steps:

Dashboard

1. Navigate to the Images tab under Compute. The image list will be long, use the search field to enter part of the name of your image and it should appear:

   

2. Select Delete Image to delete the snapshot:

   

You should now get a confirmation that the snapshot is deleted:

CLI

1. List your private images:

   $ openstack image list --private
   +--------------------------------------+-----------------+--------+
   | ID                                   | Name            | Status |
   +--------------------------------------+-----------------+--------+
   | 6edb8ab8-df9b-4339-b5d0-9e33d9d36e5d | my-test-image   | active |
   | 8fae2165-ef86-4e36-91a5-5caad9698aab | test01-snapshot | active |
   +--------------------------------------+-----------------+--------+
   

2. Delete the snapshot using the ID or name:

   $ openstack image delete 8fae2165-ef86-4e36-91a5-5caad9698aab