'Returns all hosts to send notification about router update'

def get_hosts_to_notify(self, context, router_id):

    state = agentschedulers_db.get_admin_state_up_filter()
    agents = self.get_l3_agents_hosting_routers(context, [router_id], admin_state_up=state, active=True)
    return [a.host for a in agents]
