EC2 kernel and ramdisk images should be restricted for use in launching instances

EC2 clouds have added new image types: kernel images and ramdisk images. They are identified by their ids which start with aki and ari respectively. These are meant to be specified in addition to a machine image (ami). They cannot be launched directly and when this is attempted, a backend error occurs which causes the Deltacloud Tools to throw a DeltaCloudClientException.

To handle this, it is recommended that the Find Images button in the Launch Instance dialog start with a image id filter of ami. This will then by default show valid machine images. In addition, the Launch Image dialog should issue an error message if the image id does not start with ami and the cloud is EC2.

The Cloud Viewer should restrict launching an image by right-clicking to only images that start with ami (when the cloud is EC2).

The deltacloud folks need to be contacted to see if the optional kernel images and ramdisk images are valid parameters to the launch instance REST interface. If yes, the Launch Instance dialog can be optionally expanded to add 2 new text entry fields for the Kernel image id and ramdisk image id. Each of these would have an accompanying Find button which would filter so that aki and ari images were shown. It would be a simple upgrade to the Find Image dialog to set a default initial filter which would allow filtering the image ids appropriately in each case.

Error checking could likewise ensure that the image ids for these fields started with the correct characters. For non-EC2 clouds, these fields would not be shown.