Images and snapshots¶
You use an image, or a snapshot, to boot your virtual machine.
Images contain a bootable operating system, for example, a Linux derivative as Ubuntu or CentOS.
They can have further collections of tools, packages, and configurations, for example RStudio or Apache Guacamole.
While each cloud site provides a selection of images you can use to boot up a virtual machine, de.NBI provides the same selection of images for every cloud site.
A snapshot is an exact copy of your virtual machine.
You use the snapshot of an instance as the basis for another instance.
A typical workflow can be:
- To create a virtual machine based on a de.NBI provided image, to configure the virtual machine with needed tools and packages, and to create a snapshot from that configuration. Afterward, you launch new virtual machines based on the snapshot, so that you don't need to configure it every time.
- To configure a virtual machine for a workshop, create a snapshot of that machine, and afterward, launch a virtual machine for every user based on that snapshot.
- Save your configuration and data on your root disk to continue your work later.
A snapshot preserves the full state of RAM. Therefore, you can only snapshot a virtual machine with up to a maximum of 256 GB RAM.
Create a snapshot¶
After starting a machine you can go to the instance overview tab and create a snapshot, or you create one on the detail page. A window opens where you can enter a name for your snapshot. Confirm to create a snapshot.
Don't create a snapshot of a running instance
Creating a snapshot of a running instance can lead to inconsistencies, lost data and a non-functioning and unrecoverable snapshot. Stop your instance before creating a snapshot.
- Set how many snapshots you want to see on a page and scroll through the pages.
- Filter your list of snapshots. Filter by name, project name and the OpenStack ID of the snapshot.
- Perform an action on all selected snapshots. 'Select all' to select all snapshots or
- Information about your snapshot: the name of the snapshot, the project name, and the status.
- Delete the snapshot.
Boot from a snapshot¶
After you successfully created the snapshot, you can go to the new instance tab and choose your created snapshot as an image to start a vm.