4.1 分布式安裝部署
0)叢集規劃
在hadoop102、hadoop103和hadoop104三個節點上部署Zookeeper。
1)解壓安裝
(1)解壓zookeeper安裝包到/opt/module/目錄下
[[email protected] software]$ tar -zxvf zookeeper-3.4.10.tar.gz -C /opt/module/
(2)在/opt/module/zookeeper-3.4.10/這個目錄下建立zkData
mkdir -p zkData
(3)重命名/opt/module/zookeeper-3.4.10/conf這個目錄下的zoo_sample.cfg為zoo.cfg
mv zoo_sample.cfg zoo.cfg
2)配置zoo.cfg檔案
(1)具體配置
dataDir=/opt/module/zookeeper-3.4.10/zkData
增加如下配置
#######################cluster##########################
server.2=hadoop102:2888:3888
server.3=hadoop103:2888:3888
server.4=hadoop104:2888:3888
(2)配置參數解讀
Server.A=B:C:D。
A是一個數字,表示這個是第幾号伺服器;
B是這個伺服器的ip位址;
C是這個伺服器與叢集中的Leader伺服器交換資訊的端口;
D是萬一叢集中的Leader伺服器挂了,需要一個端口來重新進行選舉,選出一個新的Leader,而這個端口就是用來執行選舉時伺服器互相通信的端口。
叢集模式下配置一個檔案myid,這個檔案在dataDir目錄下,這個檔案裡面有一個資料就是A的值,Zookeeper啟動時讀取此檔案,拿到裡面的資料與zoo.cfg裡面的配置資訊比較進而判斷到底是哪個server。
3)叢集操作
(1)在/opt/module/zookeeper-3.4.10/zkData目錄下建立一個myid的檔案
touch myid
添加myid檔案,注意一定要在linux裡面建立,在notepad++裡面很可能亂碼
(2)編輯myid檔案
vi myid
在檔案中添加與server對應的編号:如2
(3)拷貝配置好的zookeeper到其他機器上
scp -r zookeeper-3.4.10/ [email protected]:/opt/app/
scp -r zookeeper-3.4.10/ [email protected]:/opt/app/
并分别修改myid檔案中内容為3、4
(4)分别啟動zookeeper
[[email protected] zookeeper-3.4.10]# bin/zkServer.sh start
[[email protected] zookeeper-3.4.10]# bin/zkServer.sh start
[[email protected] zookeeper-3.4.10]# bin/zkServer.sh start
(5)檢視狀态
[[email protected] zookeeper-3.4.10]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: follower
[[email protected] zookeeper-3.4.10]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: leader
[[email protected] zookeeper-3.4.5]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: follower
4.2 用戶端指令行操作
指令基本文法 | 功能描述 |
help | 顯示所有操作指令 |
ls path [watch] | 使用 ls 指令來檢視目前znode中所包含的内容 |
ls2 path [watch] | 檢視目前節點資料并能看到更新次數等資料 |
create | 普通建立 -s 含有序列 -e 臨時(重新開機或者逾時消失) |
get path [watch] | 獲得節點的值 |
set | 設定節點的具體值 |
stat | 檢視節點狀态 |
delete | 删除節點 |
rmr | 遞歸删除節點 |
1)啟動用戶端
[[email protected] zookeeper-3.4.10]$ bin/zkCli.sh
2)顯示所有操作指令
[zk: localhost:2181(CONNECTED) 1] help
3)檢視目前znode中所包含的内容
[zk: localhost:2181(CONNECTED) 0] ls /
[zookeeper]
4)檢視目前節點資料并能看到更新次數等資料
[zk: localhost:2181(CONNECTED) 1] ls2 /
[zookeeper]
cZxid = 0x0
ctime = Thu Jan 01 08:00:00 CST 1970
mZxid = 0x0
mtime = Thu Jan 01 08:00:00 CST 1970
pZxid = 0x0
cversion = -1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 1
5)建立普通節點
[zk: localhost:2181(CONNECTED) 2] create /app1 "hello app1"
Created /app1
[zk: localhost:2181(CONNECTED) 4] create /app1/server101 "192.168.1.101"
Created /app1/server101
6)獲得節點的值
[zk: localhost:2181(CONNECTED) 6] get /app1
hello app1
cZxid = 0x20000000a
ctime = Mon Jul 17 16:08:35 CST 2017
mZxid = 0x20000000a
mtime = Mon Jul 17 16:08:35 CST 2017
pZxid = 0x20000000b
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 10
numChildren = 1
[zk: localhost:2181(CONNECTED) 8] get /app1/server101
192.168.1.101
cZxid = 0x20000000b
ctime = Mon Jul 17 16:11:04 CST 2017
mZxid = 0x20000000b
mtime = Mon Jul 17 16:11:04 CST 2017
pZxid = 0x20000000b
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 13
numChildren = 0
7)建立短暫節點
[zk: localhost:2181(CONNECTED) 9] create -e /app-emphemeral 8888
(1)在目前用戶端是能檢視到的
[zk: localhost:2181(CONNECTED) 10] ls /
[app1, app-emphemeral, zookeeper]
(2)退出目前用戶端然後再重新開機用戶端
[zk: localhost:2181(CONNECTED) 12] quit
[[email protected] zookeeper-3.4.10]$ bin/zkCli.sh
(3)再次檢視根目錄下短暫節點已經删除
[zk: localhost:2181(CONNECTED) 0] ls /
[app1, zookeeper]
8)建立帶序号的節點
(1)先建立一個普通的根節點app2
[zk: localhost:2181(CONNECTED) 11] create /app2 "app2"
(2)建立帶序号的節點
[zk: localhost:2181(CONNECTED) 13] create -s /app2/aa 888
Created /app2/aa0000000000
[zk: localhost:2181(CONNECTED) 14] create -s /app2/bb 888
Created /app2/bb0000000001
[zk: localhost:2181(CONNECTED) 15] create -s /app2/cc 888
Created /app2/cc0000000002
如果原節點下有1個節點,則再排序時從1開始,以此類推。
[zk: localhost:2181(CONNECTED) 16] create -s /app1/aa 888
Created /app1/aa0000000001
9)修改節點資料值
[zk: localhost:2181(CONNECTED) 2] set /app1 999
10)節點的值變化監聽
(1)在104主機上注冊監聽/app1節點資料變化
[zk: localhost:2181(CONNECTED) 26] get /app1 watch
(2)在103主機上修改/app1節點的資料
[zk: localhost:2181(CONNECTED) 5] set /app1 777
(3)觀察104主機收到資料變化的監聽
WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/app1
11)節點的子節點變化監聽(路徑變化)
(1)在104主機上注冊監聽/app1節點的子節點變化
[zk: localhost:2181(CONNECTED) 1] ls /app1 watch
[aa0000000001, server101]
(2)在103主機/app1節點上建立子節點
[zk: localhost:2181(CONNECTED) 6] create /app1/bb 666
Created /app1/bb
(3)觀察104主機收到子節點變化的監聽
WATCHER::
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/app1
12)删除節點
[zk: localhost:2181(CONNECTED) 4] delete /app1/bb
13)遞歸删除節點
[zk: localhost:2181(CONNECTED) 7] rmr /app2
14)檢視節點狀态
[zk: localhost:2181(CONNECTED) 12] stat /app1
cZxid = 0x20000000a
ctime = Mon Jul 17 16:08:35 CST 2017
mZxid = 0x200000018
mtime = Mon Jul 17 16:54:38 CST 2017
pZxid = 0x20000001c
cversion = 4
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 2
4.3 API應用
4.3.1 eclipse環境搭建
1)建立一個Maven工程
2)添加pom檔案
<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> |
3)拷貝log4j.properties檔案到項目根目錄
https://share.weiyun.com/56Zlk86
4.3.2 建立ZooKeeper用戶端
private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181"; private static int sessionTimeout = 2000; private ZooKeeper zkClient = null; @Before public void init() throws Exception { zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { // 收到事件通知後的回調函數(使用者的業務邏輯) System.out.println(event.getType() + "--" + event.getPath()); // 再次啟動監聽 try { zkClient.getChildren("/", true); } catch (Exception e) { e.printStackTrace(); } } }); } |
4.3.3 建立子節點
// 建立子節點 @Test public void create() throws Exception { // 資料的增删改查 // 參數1:要建立的節點的路徑; 參數2:節點資料 ; 參數3:節點權限 ;參數4:節點的類型 String nodeCreated = zkClient.create("/eclipse", "hello zk".getBytes(), Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT); } |
4.3.4 擷取子節點并監聽
// 擷取子節點 @Test public void getChildren() throws Exception { List<String> children = zkClient.getChildren("/", true); for (String child : children) { System.out.println(child); } // 延時阻塞 Thread.sleep(Long.MAX_VALUE); } |
4.3.5 判斷znode是否存在
// 判斷znode是否存在 @Test public void exist() throws Exception { Stat stat = zkClient.exists("/eclipse", false); System.out.println(stat == null ? "not exist" : "exist"); } |
4.4 案例實戰
監聽伺服器節點動态上下線案例
1)需求:某分布式系統中,主節點可以有多台,可以動态上下線,任意一台用戶端都能實時感覺到主節點伺服器的上下線
2)需求分析
3)具體實作:
(0)現在叢集上建立/servers節點
[zk: localhost:2181(CONNECTED) 10] create /servers "servers"
Created /servers
(1)伺服器端代碼
package com.atguigu.zkcase; import java.io.IOException; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooKeeper; import org.apache.zookeeper.ZooDefs.Ids; public class DistributeServer { private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181"; private static int sessionTimeout = 2000; private ZooKeeper zk = null; private String parentNode = "/servers"; // 建立到zk的用戶端連接配接 public void getConnect() throws IOException{ zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { } }); } // 注冊伺服器 public void registServer(String hostname) throws Exception{ String create = zk.create(parentNode + "/server", hostname.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL); System.out.println(hostname +" is noline "+ create); } // 業務功能 public void business(String hostname) throws Exception{ System.out.println(hostname+" is working ..."); Thread.sleep(Long.MAX_VALUE); } public static void main(String[] args) throws Exception { // 擷取zk連接配接 DistributeServer server = new DistributeServer(); server.getConnect(); // 利用zk連接配接注冊伺服器資訊 server.registServer(args[0]); // 啟動業務功能 server.business(args[0]); } } |
(2)用戶端代碼
package com.atguigu.zkcase; import java.io.IOException; import java.util.ArrayList; import java.util.List; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooKeeper; public class DistributeClient { private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181"; private static int sessionTimeout = 2000; private ZooKeeper zk = null; private String parentNode = "/servers"; private volatile ArrayList<String> serversList = new ArrayList<>(); // 建立到zk的用戶端連接配接 public void getConnect() throws IOException { zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { // 再次啟動監聽 try { getServerList(); } catch (Exception e) { e.printStackTrace(); } } }); } // public void getServerList() throws Exception { // 擷取伺服器子節點資訊,并且對父節點進行監聽 List<String> children = zk.getChildren(parentNode, true); ArrayList<String> servers = new ArrayList<>(); for (String child : children) { byte[] data = zk.getData(parentNode + "/" + child, false, null); servers.add(new String(data)); } // 把servers指派給成員serverList,已提供給各業務線程使用 serversList = servers; System.out.println(serversList); } // 業務功能 public void business() throws Exception { System.out.println("client is working ..."); Thread.sleep(Long.MAX_VALUE); } public static void main(String[] args) throws Exception { // 擷取zk連接配接 DistributeClient client = new DistributeClient(); client.getConnect(); // 擷取servers的子節點資訊,從中擷取伺服器資訊清單 client.getServerList(); // 業務程序啟動 client.business(); } } |
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