Unified limits cropped up in a few discussions last week. After describing the current implementation of limits, namely the attributes that make up a limit, someone asked if availability zones were on the roadmap. Ideally, it sounded like they had multiple AZs in a single region, and they wanted to be able to limit usage within the AZ. With the current implementation, regions would be the smallest unit of a deployment they could limit (e.g., limit project Foo to only using 64 compute cores within RegionOne). Instead, the idea would be to limit the number of resources for that project on an AZ within a region. What do people think about adding availability zones to limits? Should it be an official attribute in keystone? What other services would need this outside of nova? There were a few other interesting cases that popped up, but I figured we could start here. I can start another thread if needed and we can keep this specific to discussing limits + AZs. Thoughts?