蚂蚁课堂每特教育第五期互联网架构分布式协调工具zookeeper快速入门

1、分布式 Zookeeper 快速入门Zookeeper文档上这么解释 zookeeper，它是一个分布式服务框架，是 Apache Hadoop 的一个子项目，它主要是用来解决分布式应用中经常遇到的一些数据管理问题，如：命名服务、状态同步服务、集群管理、分布式应用配置项的管理等。上面的解释有点抽象，简单来说 zookeeper=文件系统+通知机制。Zookeeper 应用场景.5.中心(Dubbo+Zookeeper)分布式配置中心(存放配置文件)分布式锁 分布式队列分布式文件系统Zookeeper 单机版本Linux 环境安装 Zookeeper1.解压 zk 压缩包tar -

2、zxvf zookeeper-3.4.14.tar.gz2. 进入到 zk 目录cd zookeeper-3.4.143.在 zk 目录中创建 data 和 logs 文件夹mkdir data mkdir logs4.进入到 conf 目录，修改文件名称mv zoo_svi zoo.cfgle.cfg zoo.cfgdataDir =/usr/local/zookeeper-3.4.14/datadataLogDir=/usr/local/zookeeper-3.4.14/logs 5.启动 zk./zkServer.sh start./zkServer.sh sus单机启动成功注意：在安装

3、 Zk 的时候提前安装好jdk 环境 建议java8 以上Zookeeper 相关特性1、高效适用于大型的分布式系统. 如果写多的话性能不高，因为它要做所有节点之间的数据同步。2、可靠支持集群，大部分可用即服务可用3、顺序所有写请求由 leader 生成递增 zxid，写操作时，采用 mvcc 乐观锁机制进行写，保证所有写操作顺序。4、简洁对外提供的 api 非常实用、简洁。仅仅 7 个 api create - 在树形结构的位置中创建节点delete - 删除一个节点exists - 测试节点在指定位置上是否存在get data - 从节点上数据set data - 往节点写入输入get c

4、hilren - 检索一个节点的子节点列表sync - 等待传输数据Zookeeper 数据模型临时节点临时顺序节点持久节点持久顺序节点Java 语言操作 ZKACL 权限控制ACL 权限模型，实际上就是对树每个节点实现控制的认证有 4 种方式：world：默认方式，相当于全世界都能auth：代表已经认证通过的用户(cli 中可以通过 addauthdigest uswd 来添加当前上下文中的用户)digest：即用户名:这种方式认证，这也是业务系统中最常用的ip：使用 Ip 地址认证1.给节点设置权限/ 1.创建 zooKeeper 连接ZooKeeper zooKeeper = new Z

5、ooKeeper(35, 500, new Watcher() public void pros(WatchedEvent watchedEvent) / 1.创建 zooKeeper 连接ZooKeeper zooKeeper = new ZooKeeper(35, 500, new Watcher() public void pros(WatchedEvent watchedEvent) System.out.prln(watchedEvent.getSe().name(););/ 2.创建临时节点String s1 = zooKeepe

6、r.create(/mayikt, mayikt.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);System.out.prln(s1: + s1);/ 3.创建持久节点String s2 = zooKeeper.create(/mayikt, mayikt.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);System.out.prln(s2: + s2);/ 4.创建持久节点带顺序String s3 = zooKeeper.create

7、(/mayikt, mayikt.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT_SEQUENTIAL);System.out.prln(s3: + s3);/ 5.创建临时节点带顺序String s4 = zooKeeper.create(/mayikt, mayikt.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL_SEQUENTIAL);System.out.prln(s4: + s4);2.查询该节点必须账号实现服务与发现/ 1.创建 z

8、ooKeeper 连接ZooKeeper zooKeeper = new ZooKeeper(35, 500, new Watcher() public void pros(WatchedEvent watchedEvent) System.out.prln(watchedEvent.getSe().name(););/ 2.设置 zk 连接账号zooKeeper.addAuthInfo(digest, guest:guest123.getBytes();byte bytes = zooKeeper.getData(/mayikt_6440, null, new S(

9、);String string = new String(bytes);System.out.prln(string);System.out.prln(watchedEvent.getSe().name(););/ 2.创建账号权限 admin 可以实现读写操作Id id1 = new Id(digest, DigestAuthenticationProvider.generateDigest(admin:admin123);ACL acl1 = new ACL(ZooDefs.Perms.ALL, id1);/ 3.创建权限 guest 只允许做读操作Id id2 = new Id(dige

10、st, DigestAuthenticationProvider.generateDigest(guest:guest123);ACL acl2 = new ACL(ZooDefs.Perms.READ, id2);/ 4.添加该账号ArrayList a= new ArrayList();a.add(acl1);a.add(acl2);/ 5.创建该节点String s1 = zooKeeper.create(/memberservice, mayikt.getBytes(), a, CreateMode.PERSISTENT);System.out.prln(s1: + s1);服务端St

11、ring data = : + servort;zooKeeper.create(parentPath + / + servort, data.getBytes(),ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);Componentpublic class ApplicationRunnerImpl implements ApplicationRunner Value($servort)private String servort;Overridepublic void run(ApplicationArguments args) thro

12、ws Exception start();public void start() throws IOException, KeeperException,erruptedException ZooKeeper zooKeeper = new ZooKeeper(35, 50000, new Watcher() Overridepublic void pros(WatchedEvent watchedEvent) System.out.prln(watchedEvent.getSe().name(););String parentPath = /mayikt;Sexis

13、ts = zooKeeper.exists(parentPath, new Watcher() Overridepublic void pros(WatchedEvent event) );/ 如果当前父节点不存在的情况 就创建if (exists = null) zooKeeper.create(parentPath, mayikt.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);/ 将当前服务信息到 zk 上客户端获取Zookeeper 事件通知Zookeeper Watcher 事件通知 当节点发生变化的时候

14、修改、删除、新增 都会到通知；相关命令service keepalived startservice keepalived stopprivate sic final CountDownLatch countDownLatch = new CountDownLatch(1);public sic void main(String args) throws IOException,erruptedException, KeeperExceptionZooKeeper zooKeeper = new ZooKeeper(35, 50000, new Watcher() O

15、verridepublic void pros(WatchedEvent watchedEvent) Event.KeeperSe se = watchedEvent.getSe();/ 如果当前连接成功,则开始放心if (se = Event.KeeperSe.SyncConnected) System.out.prln(zk 连接成功);countDownLatch.countDown(););countDownLatch.await();String path = /mayikt;/ 获取该节点下子集List children = zooKeeper.getChildren(path,

16、null, new S();for (i = 0; i children.size(); i+) String pathChildren = path + / + children.get(i);byte data = zooKeeper.getData(pathChildren, null, new S();System.out.prln(服务接口地址: + new String(data);systemctl stop firewalldZookeeper简称 zk 分布式领域中遇到Zookeeper 应用场景1.分布式锁（redis 或者 zk）分布式领域中协调者2.Dubbo 服务（zk）分布式配置中心 disconfig分布式消息中