Use case 1: multisite identity service management: https://gerrit.opnfv.org/gerrit/#/c/1357/
  * Can't specify identity endpoint for token validation among several keystone servers in keystonemiddleware: https://bugs.launchpad.net/keystone/+bug/1488347
  * After discussion, community proposed using region-name to specify the keystone server for token validation. https://review.openstack.org/#/c/216579/. Verification done.

Use case 2: VNF high availability across VIM
  * proposed: Remote port for L2 communicate: https://bugs.launchpad.net/neutron/+bug/1484005
  * As Neutron PTL proposed, move to L2GW: https://bugs.launchpad.net/networking-l2gw/+bug/1529863

Use case 3:  Multisite VNF Geo site disaster recovery
  * Nova to expose quiesce / unquiesce API: https://blueprints.launchpad.net/nova/+spec/expose-quiesce-unquiesce-api, https://review.openstack.org/#/c/237881/
  * Get the real ref from volume admin_metadata in Cinder Spec: https://review.openstack.org/#/c/182150/ 
  * Get the real ref from volume admin_metadata in Cinder Code: https://review.openstack.org/#/c/252250/

Use case 4: Centralized service for resources management and/or replication (sync tenant resources like images, ssh-keys, security groups, etc)

&

Use case 5. centralized monitoring service, a user should be able to access all the logs and indicators produced by multiple openstack instances, in a centralized way
  * For use case 4&5, new project "Kingbird" proposed : https://launchpad.net/kingbird

  * Both Kingbird and Tricircle (https://wiki.openstack.org/wiki/Tricircle) are candidate solutions for use case 4 & 5.
  * Kingbird mainly aimed at fully distributed deployment scenario, Tricircle for centralized management scenario. 
  * Both Kingbird and Tricircle are new projects for multi-site cloud, could be used seperatly or combined together for different scenario.

Material for review
{{https://wiki.opnfv.org/_media/multisite/multisite_bp-bug_review_0910.pdf|multisite_bp-bug_review_0910.pdf}}