USAGE
$ mhaws [subcommand] --interface_id=ENI-id [... args passed by MHA]
required arguments:
1. failover method is ENI attach/detach
--interface_id=[ENI-id for master VIP]
2. failover method is RouteTable change destination
--route_table_id=[RouteTable-id]
--vip=[master VIP]
subcommand:
master_ip_failover
master_ip_online_change
shutdown