Comment 1 for bug 1360119

"operation failed: filter 'nova-nodhcp' already exists with uuid 59970732-ca52-4521-ba0c-d001049d846"

Libvirt aims to ensure uniqueness of name + uuid. So if you have a filter already existing with name FOO and UUID of XXXXX, and you try to define a new one with name FOO but UUID of YYYY it considers that a mistake.. The fix is to ensure you always use the original UUID when trying to replace the config of the existing filter.