We should support to return a list of servers according to users' requirements.
In this patch, marker, limit, sort_key and sort_dir were added in server list
API.
- marker is used to display a list of servers after marker
- limit is used to determinate the maximum number of servers to display
- sort_key is used to sort the returned server list by specified key value
- sort_dir is used to select a sort direction
DocImpact
APIImpact
Change-Id: Id70e965794c82a0a29e53d4364f65b0f39042c7c
Closes-Bug: #1726665
Xinran