Zookeeper的分布式安装和API介绍:
安装教程
在datanode1、datanode2和datanode3三个节点上部署Zookeeper。
步骤
解压zookeeper安装包到/opt/module/目录下
tar -zxvf zookeeper-3.4.10.tar.gz -C /opt/module/
/opt/module/zookeeper-3.4.10/这个目录下创建zkData
mkdir -p zkData
重命名/opt/module/zookeeper-3.4.10/conf这个目录下的zoo_sample.cfg为zoo.cfg
mv zoo_sample.cfg zoo.cfg
配置zoo.cfg文件
#######################cluster##########################
server.2=datanode1:2888:3888
server.3=datanode2:2888:3888
server.4=datanode3:2888:3888
server.A=B:C:D。
A是一个数字,表示这个是第几号服务器;
B是这个服务器的ip地址或者主机名;
C是这个服务器与集群中的Leader服务器交换信息的端口;
D是万一集群中的Leader服务器挂了,需要一个端口来重新进行选举,选出一个新的Leader,而这个端口就是用来执行选举时服务器相互通信的端口。
集群模式下配置一个文件myid,这个文件在dataDir目录下,这个文件里面有一个数据就是A的值,Zookeeper启动时读取此文件,拿到里面的数据与zoo.cfg里面的配置信息比较从而判断到底是哪个server。
- 在/opt/module/zookeeper-3.4.10/zkData目录下创建一个myid的文件
touch myid
编辑myid文件,各个节点的值根据配置文件zoo.cfg来
拷贝配置好的zookeeper到其他机器上并分别修改myid文件中内容为3、4
touch myid
启动脚本
#!/bin/sh
echo "starting zookeeper server..."
hosts="datanode1 datanode2 datanode3"
for host in $hosts
do
ssh $host "source /etc/profile; /opt/module/zookeeper-3.4.10/bin/zkServer.sh start"
done
停止脚本换成stop即可
- 查看zhua状态
zkServer.sh status
客户端命令行操作
help | 显示所有操作命令 |
ls path [watch] | 使用 ls 命令来查看当前znode中所包含的内容 |
ls2 path [watch] | 查看当前节点数据并能看到更新次数等数据 |
create | 普通创建 -s 含有序列 -e 临时(重启或者超时消失) |
get path [watch] | 获得节点的值 |
set | 设置节点的具体值 |
stat | 查看节点状态 |
delete | 删除节点 |
rmr | 递归删除节点 |
Shell命令
启动客户端
bin/zkCli.sh
显示所有操作命令
[zk: localhost:2181(CONNECTED) 0] help
ZooKeeper -server host:port cmd args
connect host:port
get path [watch]
ls path [watch]
set path data [version]
rmr path
delquota [-n|-b] path
quit
printwatches on|off
create [-s] [-e] path data acl
stat path [watch]
close
ls2 path [watch]
history
listquota path
setAcl path acl
getAcl path
sync path
redo cmdno
addauth scheme auth
delete path [version]
setquota -n|-b val path
查看当前znode中所包含的内容
[zk: localhost:2181(CONNECTED) 1] ls /
[isr_change_notification, test, hbase, zookeeper, admin, consumers, cluster, config, latest_producer_id_block,
kafka-manager, brokers, controller_epoch]
查看当前节点数据并能看到更新次数等数据
[zk: localhost:2181(CONNECTED) 2] ls2 /
[isr_change_notification, test, hbase, zookeeper, admin, consumers, cluster, config, latest_producer_id_block, kafka-manager, brokers, controller_epoch]
cZxid = 0x0
ctime = Thu Jan 01 08:00:00 CST 1970
mZxid = 0x0
mtime = Thu Jan 01 08:00:00 CST 1970
pZxid = 0x1200000104
cversion = 100
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 12
创建普通节点
[zk: localhost:2181(CONNECTED) 3] create /app1 "hello app1"
Created /app1
[zk: localhost:2181(CONNECTED) 4] create /app1/server101 "192.168.1.101"
Created /app1/server101
获得节点的值
[zk: localhost:2181(CONNECTED) 5] get /app1
hello app1
cZxid = 0x120000010a
ctime = Sat Jan 05 13:34:15 CST 2019
mZxid = 0x120000010a
mtime = Sat Jan 05 13:34:15 CST 2019
pZxid = 0x120000010b
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 10
numChildren = 1
[zk: localhost:2181(CONNECTED) 6] get /app1/server101
192.168.1.101
cZxid = 0x120000010b
ctime = Sat Jan 05 13:34:46 CST 2019
mZxid = 0x120000010b
mtime = Sat Jan 05 13:34:46 CST 2019
pZxid = 0x120000010b
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 13
numChildren = 0
创建短暂节点
[zk: localhost:2181(CONNECTED) 7] create -e /app-emphemeral 8888
Created /app-emphemeral
## 在当前客户端是能查看到的
[zk: localhost:2181(CONNECTED) 8] ls /
[app1, isr_change_notification, test, hbase, zookeeper, admin, consumers, cluster, config, latest_producer_id_block, kafka-manager, app-emphemeral, brokers, controller_epoch]
## 退出当前客户端然后再重启客户端
[zk: localhost:2181(CONNECTED) 9] quit
Quitting...
2019-01-06 17:43:54,558 [myid:] - INFO [main:ZooKeeper@684] - Session: 0x1681924b94d0014 closed
2019-01-06 17:43:54,564 [myid:] - INFO [main-EventThread:ClientCnxn$EventThread@519] - EventThread shut down for session: 0x1681924b94d0014
## 重启客户端
[hadoop@datanode1 bin]$ ./zkCli.sh
....
2019-01-06 17:46:04,711 [myid:] - INFO [main-SendThread(localhost:2181):ClientCnxn$SendThread@1299] - Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x1681924b94d0015, negotiated timeout = 30000 WATCHER:: WatchedEvent state:SyncConnected type:None path:null
## 再次查看根目录下短暂节点已经删除 [zk: localhost:2181(CONNECTED) 0] ls /
[app1, isr_change_notification, test, hbase, zookeeper, admin, consumers, cluster, config, latest_producer_id_block, kafka-manager, brokers, controller_epoch]
创建带序号的节点
## 先创建一个普通的根节点app2
[zk: localhost:2181(CONNECTED) 1] create /app2 "app2"
Created /app2
## 创建带序号的节点
[zk: localhost:2181(CONNECTED) 2] create /app2 "app2"
[zk: localhost:2181(CONNECTED) 3] create -s /app2/aa 888
Created /app2/aa0000000000
[zk: localhost:2181(CONNECTED) 4] create -s /app2/bb 888
Created /app2/bb0000000001
[zk: localhost:2181(CONNECTED) 5] create -s /app2/cc 888
Created /app2/cc0000000002
##如果原节点下有1个节点,则再排序时从1开始,以此类推。
[zk: localhost:2181(CONNECTED) 6] create -s /app1/aa 888
Created /app1/aa0000000001
修改节点数据值
[zk: localhost:2181(CONNECTED) 8] set /app1 999
cZxid = 0x120000010a
ctime = Sat Jan 05 13:34:15 CST 2019
mZxid = 0x1200000116
mtime = Sat Jan 05 14:12:56 CST 2019
pZxid = 0x1200000114
cversion = 3
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 3
节点的值变化监听
在datanode1主机上注册监听/app1节点数据变化
[zk: localhost:2181(CONNECTED) 9] get /app1 watch
999
cZxid = 0x120000010a
ctime = Sat Jan 05 13:34:15 CST 2019
mZxid = 0x1200000116
mtime = Sat Jan 05 14:12:56 CST 2019
pZxid = 0x1200000114
cversion = 3
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 3
在datanode2主机上修改/app1节点的数据
[zk: localhost:2181(CONNECTED) 0] set /app1 777
cZxid = 0x120000010a
ctime = Sat Jan 05 13:34:15 CST 2019
mZxid = 0x1200000118
mtime = Sat Jan 05 14:14:43 CST 2019
pZxid = 0x1200000114
cversion = 3
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 3
datanode1主机上的变化
[zk: localhost:2181(CONNECTED) 10]
WATCHER:: WatchedEvent state:SyncConnected type:NodeDataChanged path:/app1
节点的子节点变化监听(路径变化)
在datanode1主机上注册监听/app1节点的子节点变化
[zk: localhost:2181(CONNECTED) 0] ls /app1 watch
[aa0000000001, server101, cc0000000002]
在datanode2主机/app1节点上创建子节点
[zk: localhost:2181(CONNECTED) 1] create /app1/bb 666
Created /app1/bb
观察datanode1主机收到子节点变化的监听
WATCHER::
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/app1
删除节点
[zk: localhost:2181(CONNECTED) 2] delete /app1/bb
递归删除节点
[zk: localhost:2181(CONNECTED) 3] rmr /app2
查看节点状态
[zk: localhost:2181(CONNECTED) 1] stat /app1
cZxid = 0x120000010a
ctime = Sat Jan 05 13:34:15 CST 2019
mZxid = 0x1200000118
mtime = Sat Jan 05 14:14:43 CST 2019
pZxid = 0x120000011d
cversion = 5
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 3
API应用
IDEA环境搭建
创建一个Maven工程
添加pom文件
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.10</version>
</dependency>
</dependencies>
log4j.propertie
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
创建ZooKeeper客户端
public class ZKDemo {
private String connect = "datanode1:2181,datanode2:2181,datanode3:2181";
private int timeout = 2000;
private ZooKeeper zooKeeper = null; //获取Zookeeper的客户端
@Before
public void getClient() throws Exception {
zooKeeper = new ZooKeeper(connect, timeout, new Watcher() {
//接收到Zookeeper发来的通知以后做出的处理措施(自己处理的业务逻辑)
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println(watchedEvent.getType() + "-----" + watchedEvent.getPath());
}
});
}
创建子节点
//创建节点
@Test
public void testCreate() throws KeeperException, InterruptedException {
// 参数1:要创建的节点的路径; 参数2:节点数据 ; 参数3:节点权限 ;参数4:节点的类型
String path = zooKeeper.create(
"/cainiaoqingfeng",
"bigtadaLearing".getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT);
System.out.println(path);
}
[zk: localhost:2181(CONNECTED) 2] ls /
[test, cainiaoqingfeng, consumers, latest_producer_id_block, controller_epoch, app2, app1, isr_change_notification,
hbase, admin, zookeeper, config, cluster, kafka-manager, brokers]
判断节点是否存在
public void testExist() throws KeeperException, InterruptedException {
Stat stat = zooKeeper.exists("/cainiaoqingfeng", false);
System.out.println(stat==null?"not exist":"exist");
}
循环监听
try {
List<String> children = zooKeeper.getChildren("/cainiaoqingfeng", true);
for (String child : children) {
System.out.println(child);
} } catch (Exception e) {
e.printStackTrace();
}
//在创建Zookeeper客户端的代码中加此以上代码
改变节点的内容
public void testSet() throws KeeperException, InterruptedException {
Stat stat = zooKeeper.setData("/cainiaoqingfeng/bigdata", "I love bigdata".getBytes(), -1); }
[zk: localhost:2181(CONNECTED) 20] get /cainiaoqingfeng/bigdata
I love bigdata
cZxid = 0x1200000126
ctime = Sat Jan 05 16:11:19 CST 2019
mZxid = 0x1200000136
mtime = Sat Jan 05 16:27:51 CST 2019
pZxid = 0x1200000126
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 14
监听器原理
过程
- 先要有一个main()线程
- 在main线程中创建Zookeeper客户端,这时就会创建两个线程,一个负责网络连接通信(connet),一个负责监听(listener)。
- 通过connect线程将注册的监听事件发送给Zookeeper。
- 在Zookeeper的注册监听器列表中将注册的监听事件添加到列表中。
- Zookeeper监听到有数据或路径变化,就会将这个消息发送给listener线程。
- listener线程内部调用了process()方法。
常见监听
2.常见的监听
(1)监听节点数据的变化:
get path [watch]
(2)监听子节点增减的变化
ls path [watch]
写数据
ZooKeeper 的写数据流程主要分为以下几步,如图所示:
流程
- 比如 Client 向 ZooKeeper 的 Server1 上写数据,发送一个写请求。
- 如果Server1不是Leader,那么Server1 会把接受到的请求进一步转发给Leader,因为每个ZooKeeper的Server里面有一个是Leader。这个Leader 会将写请求广播给各个Server,比如Server1和Server2, 各个Server写成功后就会通知Leader。
- 当Leader收到大多数 Server 数据写成功了,那么就说明数据写成功了。如果这里三个节点的话,只要有两个节点数据写成功了,那么就认为数据写成功了。写成功之后,Leader会告诉Server1数据写成功了。
- Server1会进一步通知 Client 数据写成功了,这时就认为整个写操作成功。ZooKeeper 整个写数据流程就是这样的。
服务器节点动态上下线
ZkServer
import org.apache.zookeeper.*; import java.io.IOException; public class zkServer {
private static String connect = "datanode1:2181,datanode2:2181,datanode3:2181"; //写自己的集群的ip和端口
private static int timeout = 2000;
private static ZooKeeper zooKeeper = null;
private static String parentPahth = "/servers/"; public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
//获取Zookeeper的客户端
getClient();
//启动注册
registsServer(args[0]);
//业务逻辑
business(args[0]);
} private static void business(String hostname) throws InterruptedException {
System.out.println(hostname+" is working...");
Thread.sleep(Long.MAX_VALUE); } private static void registsServer(String hostname) throws KeeperException, InterruptedException {
//创建临时节点
String path = zooKeeper.create(parentPahth + "server",
hostname.getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.EPHEMERAL_SEQUENTIAL);
System.out.println(hostname+" is online "+path);
Thread.sleep(Long.MAX_VALUE);
} private static void getClient() throws IOException {
zooKeeper = new ZooKeeper(connect, timeout, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println(watchedEvent.getType() + "**********" + watchedEvent.getPath());
}
});
}
}
ZkClient
import org.apache.zookeeper.*; import java.io.IOException; public class zkServer {
private static String connect = "datanode1:2181,datanode2:2181,datanode3:2181"; //写自己的集群的ip和端口
private static int timeout = 2000;
private static ZooKeeper zooKeeper = null;
private static String parentPahth = "/servers/"; public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
//获取Zookeeper的客户端
getClient();
//启动注册
registsServer(args[0]);
//业务逻辑
business(args[0]);
} private static void business(String hostname) throws InterruptedException {
System.out.println(hostname+" is working...");
Thread.sleep(Long.MAX_VALUE); } private static void registsServer(String hostname) throws KeeperException, InterruptedException {
//创建临时节点
String path = zooKeeper.create(parentPahth + "server",
hostname.getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.EPHEMERAL_SEQUENTIAL);
System.out.println(hostname+" is online "+path);
Thread.sleep(Long.MAX_VALUE);
} private static void getClient() throws IOException {
zooKeeper = new ZooKeeper(connect, timeout, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println(watchedEvent.getType() + "**********" + watchedEvent.getPath());
}
});
}
}