Deploy nfs-ganesha

Nfs-ganesha can be used as a proxy when mounting ceph file shares. Because nfs-ganesha backend will be supported in manila service soon, we would like to allow users deploy nfs-ganesha in Overcloud so they can use it as a backend in manila. Major benefit is that tenants (user instances) then don't need direct access to the ceph public network (storage network in Overcloud), but only to the nfs-ganesha servers.

In the first step (Pike release), nfs-ganesha service will be deployed on controller nodes together with manila-share service and it will use active/passive HA mode managed by Pacemaker. A new virtual IP on external network will be used. Nfs-ganesha will listen on this VIP, both virtual IP and nfs-ganesha service failover will be handled by pacemaker. User instances will use the VIP on a new isolated storage-nfs network to access nfs-ganesha when mounting shares (so there is no need to provide access to the ceph public network for them).

This is not a true scale out solution because it uses a shared ganesha server and a shared storage nfs-network for all tenants (and relies on neutron security groups to provide security between tenants). We plan to develop a scale-out solution as a follow-on step.

Related mail-thread:
http://lists.openstack.org/pipermail/openstack-dev/2017-April/115169.html