When you have created a custom workflow or configuration on the API side, you can create a snapshot for your own use. In OpenStack, an instance snapshot is an image. The only difference between an image that has been uploaded directly to glance and an image you create by snapshot is that an image created by snapshot has additional properties in the glance database and defaults to being private.
You can create an snapshot from a running server instance, but if you want to preserve data, you must shut down the source VM and verify the instance status is
SHUTOFF before creating the snapshot.
Before creating the snapshot and/or image, you'll want to make sure that cloud-init is installed on your instance as well as qemu-guest-agent – If your instance was based on one of the JS-Featured-API images, both cloud-init and qemu-guest-agent should be present unless you explicitly removed them.
Log in to the Horizon dashboard and go to Project → Compute → Instances
Find the instance you want to snapshot and note the Create Snapshot button.
Click Create Snapshot
In the dialog box that comes up, give it a descriptive name. A best practice is to give is a name that describes the image and has rudimentary version information - e.g. primary-gateway-image-v1
Click Create Snapshot once you've given it a name.
Once you do this, it will take you to the Project → Compute → Images screen. You can find your pending snapshot by using the filter.
You'll see it in state "Queued". This is normal.
Please note that if you refresh this screen or filter/unfilter that it might take 10-15 seconds to refresh the list. It has to pull the entire image list again each time.
After a few minutes (or possibly more), depending on system load, you should see it change status to Active. At this point you can click "Launch" and launch a new instance from it using the step by step launch instructions on Using the OpenStack Horizon GUI Interface
If you've launched instances previously on the API side with either Horizon or the CLI and left your network, security groups, and keys intact, you can start with the step "Launching an instance - Step 1"
If your snapshot stays in Queued status for more than 45 minutes, there might be an issue with either the snapshot or the Glance image store in OpenStack. In this case, you should contact firstname.lastname@example.org with your allocation number, the UID of snapshot (which you can get by clicking on it) and the UID of the instance you are trying to snapshot.