How to Launch an Instance from a Volume

Red Hat has a good article on launching an instance from a volume. The summary is:

1. Choose an image to create a bootable volume from:

    $nova image-list
   

2. Create a bootable volume from the image using the image ID:

    # cinder create --image-id e0b7734d-2331-42a3-b19e-067adc0da17d --display-name my-boot-vol 8
   

3. List volumes:

    $ cinder list
   

4. Launch the instance:

    $ nova boot --flavor 2 --image e0b7734d-2331-42a3-b19e-067adc0da17d \ --block_device_mapping vda=3195a5a7-fd0d-4ac3-b919-7ba6cbe11d46:::0 myInstanceFromVolume
   

5. Observe that the volume is attached to a server when you list volumes:

    $ nova volume-list