Managing your cloud resources with OpenStack: Difference between revisions

If running a persistent machine, booting from a volume is a safer option. When creating a VM booting from an image, rather than a volume, it will store the VM on the local disk of the actual machine running the VM. If something went wrong with that machine or its disk, there is a good chance your VM would be lost. Volume storage has a built in redundancy which will protect your volumes from hardware failure.

There are several ways to boot a VM from a volume, you can either create a volume (or use a pre-existing one) and then select to boot from it, or you can create a volume as part of the process of launching a VM.

If creating a volume first, proceed in the same way as described above, except that you choose a volume source. You can either use an image or another volume as the source for your new volume. When launching a VM from a pre-existing volume OpenStack does not load an operating system onto the volume. This is what you would want if you were booting from a volume which you have already been working with previously, containing a working and configured operating system. However, if you create an empty volume as done above, there will be no operating system loaded to boot from so you will not be able to use your VM.

If creating a volume as part of the process of launching the VM, select <code>Boot from image (creates a new volume)</code> select the image to use and the size of the volume. The default device name of <code>vda</code> should work well. If this volume is something you would like to remain longer than the VM ensure that the "Delete on Terminate" check box is unchecked. If you are unsure about this option, it is better to leave this box unchecked as you can always manually delete the volume later as an extra step.