I've set up and configured the OpenStack Cloud plugin with one template. When I try to launch a slave based on that template (via Manage nodes) all I get is: "Error. Boot failed".

After studying the logs and the network traffic I found the cause. The plugin tries to resolve the image ID based on the Image name that I configured. (See jenkins.plugins.openstack.compute.internal.OpenStack.getImageIdFor(String name)).

This results is an API call to the images API:
HTTP/1.1 GET v1/images?status=ACTIVE&name=My_Image
The API however expects a lowercase status instead of uppercase (see also http://developer.openstack.org/api-ref-image-v1.html). So the response body is:
{"images": []}.

The result of this is that the plugin tries to provision an instance via the API without providing an imageRef.

So there are essentially two issues:
1. The plugin makes the wrong API call
2. The plugin doesn't handle the situation where no images are returned correctly.

This bug was introduced with commit 50dd47d798bcd79a99ebfb62e51cb2c2d057777f.