示例#1
0
// Run blocks implementing the scheduler module.
func Run(conn db.Conn) {
	var sched scheduler
	for range conn.TriggerTick(30, db.MinionTable, db.EtcdTable, db.ContainerTable,
		db.PlacementTable).C {
		minion, err := conn.MinionSelf()
		if err != nil || !conn.EtcdLeader() || minion.Role != db.Master ||
			minion.PrivateIP == "" {
			sched = nil
			continue
		}

		if sched == nil {
			ip := minion.PrivateIP
			sched = newSwarm(docker.New(fmt.Sprintf("tcp://%s:2377", ip)))
			time.Sleep(60 * time.Second)
		}

		placements := conn.SelectFromPlacement(nil)
		connections := conn.SelectFromConnection(nil)
		// Each time we run through this loop, we may boot or terminate
		// containers.  These modification should, in turn, be reflected in the
		// database themselves.  For this reason, we attempt to sync until no
		// database modifications happen (up to an arbitrary limit of three
		// tries).
		for i := 0; i < 3; i++ {
			dkc, err := sched.list()
			if err != nil {
				log.WithError(err).Warning("Failed to get containers.")
				break
			}

			var boot []db.Container
			var term []string
			conn.Transact(func(view db.Database) error {
				term, boot = syncDB(view, dkc)
				return nil
			})

			if len(term) == 0 && len(boot) == 0 {
				break
			}
			sched.terminate(term)
			sched.boot(boot, placements, connections)
		}
	}
}