These are files containing the cloud image of the Debian GNU/Linux
operating system designed for OpenStack.
The files in this directory are specifically for
The files here are qcow2 or raw images, ready to use.
Once you have downloaded the image, you would typically need to upload it to Glance, using a command like this one:
glance image-create --name="Debian Jessie 64-bit" \ --disk-format=qcow2 --container-format=bare \ --property architecture=x86_64 \ --progress \ --file debian-8.0.0-openstack-amd64.qcow2
Then you can boot a new virtual machine instance using the uploaded image ID.
If your platform supports the EC2 style metadata server (which is contacted by cloud-init), and also supports an HDD image (using either raw or qcow2 format), then most likely it will work. Note that it will not work on Amazon EC2 if you are not using the HVM mode.
There are files here (MD5SUMS, SHA1SUMS, etc.) which contain checksums of the images. These checksum files are also signed - see MD5SUMS.sign, SHA1SUMS.sign, etc. Once you've downloaded an image, you can check:
For more information about how to do these steps, read the verification guide.
Other questions can be forwarded to the OpenStack packaging team: openstack-devel at lists.alioth.debian.org.