Zookeeper实现分布式应用的(主节点HA)及客户端动态更新主节点状态

优速盾-小U • 2022年8月20日 02:16 • 行业资讯 • 阅读 546

某分布式系统中，主节点可以有多台，可以动态上下线
任意一台客户端都能实时感知到主节点服务器的上下线
服务端逻辑：

服务端启动时在zookeeper集群中 /services节点写入一个临时节点，该临时节点内容为该节点的名称。当服务端下线或者宕机时zookeeper会将该节点删除

客户端逻辑

客户端启动时会查找/services 下所有节点 并将节点名输出，当节点变化时，会重新查找所有节点，并将节点名输出

 import org.apache.zookeeper.CreateMode import org.apache.zookeeper.Watcher import org.apache.zookeeper.ZooDefs import org.apache.zookeeper.ZooKeeper /** * 服务端 */ object DistributedServer {  private val CONNECT_STRING: String = "192.168.84.132:2181,192.168.84.133:2181,192.168.84.134:2181"  private val SESSION_TIMEOUT: Int = 2000  private val zooKeeper: ZooKeeper by lazy { ZooKeeper(CONNECT_STRING, SESSION_TIMEOUT, Watcher { event ->  println("${event?.type}-->${event?.path}")  zooKeeper.getChildren("/", true) }) } @JvmStatic fun main(args: Array<String>) { val serviceName = args[0] zooKeeper.create("/services/service", serviceName.toByteArray(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL) println("serviceName --> $serviceName create") println("$serviceName start working.....") Thread.sleep(Long.MAX_VALUE) } }

 import org.apache.zookeeper.Watcher import org.apache.zookeeper.ZooKeeper import org.apache.zookeeper.data.Stat /** * 客户端 */ object DistributedClient {  private val CONNECT_STRING: String = "192.168.84.132:2181,192.168.84.133:2181,192.168.84.134:2181"  private val SESSION_TIMEOUT: Int = 2000 private val zooKeeper: ZooKeeper by lazy { ZooKeeper(CONNECT_STRING, SESSION_TIMEOUT, Watcher { event -> println("${event?.type}-->${event?.path}") getServiceList() }) }  @Volatile private lateinit var services: ArrayList<String> @JvmStatic fun main(args: Array<String>) { getServiceList() println("client start working.....") Thread.sleep(Long.MAX_VALUE) } private fun getServiceList() {  val serviceList = zooKeeper.getChildren("/services", true)  val tempList = arrayListOf<String>() serviceList  .map { zooKeeper.getData("/services/" + it, false, Stat())} .mapTo(tempList) { String(it) } services = tempList println(services) } }