Zookeeper學習之路（三）shell操做

時間 2019-11-21

標籤 zookeeper 學習之路 shell 欄目 Zookeeper 简体版

原文原文鏈接

Zookeeper的shell操做

Zookeeper命令工具

在啓動Zookeeper服務以後，輸入如下命令，鏈接到Zookeeper服務：java

[hadoop@hadoop1 ~]$ zkCli.sh -server hadoop2:2181

 1 [hadoop@hadoop1 ~]$ zkCli.sh -server hadoop2:2181
 2 Connecting to hadoop2:2181
 3 2018-03-21 19:55:53,744 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.10-39d3a4f269333c922ed3db283be479f9deacaa0f, built on 03/23/2017 10:13 GMT
 4 2018-03-21 19:55:53,748 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=hadoop1
 5 2018-03-21 19:55:53,749 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.8.0_73
 6 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Oracle Corporation
 7 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=/usr/local/jdk1.8.0_73/jre
 8 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=/home/hadoop/apps/zookeeper-3.4.10/bin/../build/classes:/home/hadoop/apps/zookeeper-3.4.10/bin/../build/lib/*.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../lib/slf4j-log4j12-1.6.1.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../lib/slf4j-api-1.6.1.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../lib/netty-3.10.5.Final.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../lib/log4j-1.2.16.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../lib/jline-0.9.94.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../zookeeper-3.4.10.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../src/java/lib/*.jar:/home/hadoop/apps/zookeeper-3.4.10/bin/../conf::/usr/local/jdk1.8.0_73/lib:/usr/local/jdk1.8.0_73/jre/lib
 9 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
10 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=/tmp
11 2018-03-21 19:55:53,751 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>
12 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Linux
13 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=amd64
14 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=2.6.32-573.el6.x86_64
15 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=hadoop
16 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/home/hadoop
17 2018-03-21 19:55:53,752 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/home/hadoop
18 2018-03-21 19:55:53,755 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=hadoop2:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@5c29bfd
19 Welcome to ZooKeeper!
20 2018-03-21 19:55:53,789 [myid:] - INFO  [main-SendThread(hadoop2:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server hadoop2/192.168.123.103:2181. Will not attempt to authenticate using SASL (unknown error)
21 JLine support is enabled
22 2018-03-21 19:55:53,931 [myid:] - INFO  [main-SendThread(hadoop2:2181):ClientCnxn$SendThread@876] - Socket connection established to hadoop2/192.168.123.103:2181, initiating session
23 2018-03-21 19:55:53,977 [myid:] - INFO  [main-SendThread(hadoop2:2181):ClientCnxn$SendThread@1299] - Session establishment complete on server hadoop2/192.168.123.103:2181, sessionid = 0x262486284b70000, negotiated timeout = 30000
24 
25 WATCHER::
26 
27 WatchedEvent state:SyncConnected type:None path:null
28 [zk: hadoop2:2181(CONNECTED) 0]

View Code

鏈接成功以後，系統會輸出Zookeeper的相關環境及配置信息，並在屏幕輸出「welcome to Zookeeper！」等信息。node

輸入help以後，屏幕會輸出可用的Zookeeper命令，以下圖所示shell

使用Zookeeper命令的簡單操做步驟

(1) 使用ls命令查看當前Zookeeper中所包含的內容：ls /apache

[zk: hadoop2:2181(CONNECTED) 1] ls / [zookeeper]
[zk: hadoop2:2181(CONNECTED) 2]

(2) 建立一個新的Znode節點"aa"，以及和它相關字符，執行命令：create /aa "my first zk"，默認是不帶編號的api

[zk: hadoop2:2181(CONNECTED) 2] create /aa "my first zk" Created /aa
[zk: hadoop2:2181(CONNECTED) 3]

　　建立帶編號的持久性節點"bb"，session

[zk: localhost:2181(CONNECTED) 1] create -s /bb "bb"
Created /bb0000000001
[zk: localhost:2181(CONNECTED) 2]

　　建立不帶編號的臨時節點"cc"app

[zk: localhost:2181(CONNECTED) 2] create -e /cc "cc"
Created /cc
[zk: localhost:2181(CONNECTED) 3]

　　建立帶編號的臨時節點"dd"socket

[zk: localhost:2181(CONNECTED) 3] create -s -e /dd "dd"
Created /dd0000000003
[zk: localhost:2181(CONNECTED) 4]

(3) 再次使用ls命令來查看如今Zookeeper的中所包含的內容：ls /ide

[zk: localhost:2181(CONNECTED) 4] ls /
[cc, dd0000000003, zookeeper, bb0000000001]
[zk: localhost:2181(CONNECTED) 5] 工具

此時看到，aa節點已經被建立。

關閉本次鏈接回話session，再從新打開一個鏈接

[zk: localhost:2181(CONNECTED) 5] close 2018-03-22 13:03:29,137 [myid:] - INFO  [main:ZooKeeper@684] - Session: 0x1624c10e8d90000 closed
[zk: localhost:2181(CLOSED) 6] 2018-03-22 13:03:29,139 [myid:] - INFO  [main-EventThread:ClientCnxn$EventThread@519] - EventThread shut down for session: 0x1624c10e8d90000

[zk: localhost:2181(CLOSED) 6] ls /
Not connected
[zk: localhost:2181(CLOSED) 7] connect hadoop1:2181

從新查看，臨時節點已經隨着上一次的會話關閉自動刪除了

[zk: hadoop1:2181(CONNECTED) 8] ls /
[zookeeper, bb0000000001]
[zk: hadoop1:2181(CONNECTED) 9]

(4) 使用get命令來確認第二步中所建立的Znode是否包含咱們建立的字符串，執行命令：get /aa

[zk: hadoop2:2181(CONNECTED) 4] get /aa my first zk
cZxid = 0x100000002
ctime = Wed Mar 21 20:01:02 CST 2018
mZxid = 0x100000002
mtime = Wed Mar 21 20:01:02 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: hadoop2:2181(CONNECTED) 5]

(5) 接下來經過set命令來對zk所關聯的字符串進行設置，執行命令：set /aa haha123

[zk: hadoop2:2181(CONNECTED) 6] set /aa haha123 
cZxid = 0x100000002
ctime = Wed Mar 21 20:01:02 CST 2018
mZxid = 0x100000004
mtime = Wed Mar 21 20:04:10 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
[zk: hadoop2:2181(CONNECTED) 7]

(6) 再次使用get命令來查看，上次修改的內容，執行命令：get /aa

[zk: hadoop2:2181(CONNECTED) 7] get /aa
haha123
cZxid = 0x100000002
ctime = Wed Mar 21 20:01:02 CST 2018
mZxid = 0x100000004
mtime = Wed Mar 21 20:04:10 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
[zk: hadoop2:2181(CONNECTED) 8]

(7) 下面咱們將剛纔建立的Znode刪除，執行命令：delete /aa

[zk: hadoop2:2181(CONNECTED) 8] delete /aa
[zk: hadoop2:2181(CONNECTED) 9]

(8) 最後再次使用ls命令查看Zookeeper中的內容，執行命令：ls /

[zk: hadoop2:2181(CONNECTED) 9] ls /
[zookeeper]
[zk: hadoop2:2181(CONNECTED) 10]

通過驗證，zk節點已經刪除。

(9) 退出，執行命令：quit

[zk: hadoop2:2181(CONNECTED) 10] quit
Quitting...
2018-03-21 20:07:11,133 [myid:] - INFO  [main:ZooKeeper@684] - Session: 0x262486284b70000 closed
2018-03-21 20:07:11,139 [myid:] - INFO  [main-EventThread:ClientCnxn$EventThread@519] - EventThread shut down for session: 0x262486284b70000
[hadoop@hadoop1 ~]$

狀態信息

查看一個文件的狀態信息

[zk: localhost:2181(CONNECTED) 1] stat /a
cZxid = 0x200000009
ctime = Thu Mar 22 13:07:19 CST 2018
mZxid = 0x200000009
mtime = Thu Mar 22 13:07:19 CST 2018
pZxid = 0x200000009
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 1
numChildren = 0
[zk: localhost:2181(CONNECTED) 2]

詳細解釋：

zxid：一個事務編號，zookeeper集羣內部的全部事務，都有一個全局的惟一的順序的編號

　　它由兩部分組成：就是一個 64位的長整型 long

　　高32位: 用來標識leader關係是否改變，如 0x2　　

　　低32位：用來作當前這個leader領導期間的全局的遞增的事務編號，如 00000009

狀態屬性	說明
cZxid	數據節點建立時的事務ID
ctime	數據節點建立時的時間
mZxid	數據節點最後一次更新時的事務ID
mtime	數據節點最後一次更新時的時間
pZxid	數據節點的子節點列表最後一次被修改（是子節點列表變動，而不是子節點內容變動）時的事務ID
cversion	子節點的版本號
dataVersion	數據節點的版本號
aclVersion	數據節點的ACL版本號
ephemeralOwner	若是節點是臨時節點，則表示建立該節點的會話的SessionID；若是節點是持久節點，則該屬性值爲0
dataLength	數據內容的長度
numChildren	數據節點當前的子節點個數

（1）修改節點a的數據，mZxid、dataVersion、dataLength 存儲信息發生變化

[zk: localhost:2181(CONNECTED) 2] set /a 'aaa'
cZxid = 0x200000009
ctime = Thu Mar 22 13:07:19 CST 2018 mZxid = 0x20000000a
mtime = Thu Mar 22 13:12:53 CST 2018
pZxid = 0x200000009
cversion = 0 dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0 dataLength = 3
numChildren = 0
[zk: localhost:2181(CONNECTED) 3]

（2）建立新的節點b，狀態信息都會發生變化，zxid的事物ID也會增長

[zk: localhost:2181(CONNECTED) 5] stat /b
cZxid = 0x20000000b
ctime = Thu Mar 22 13:15:56 CST 2018
mZxid = 0x20000000b
mtime = Thu Mar 22 13:15:56 CST 2018
pZxid = 0x20000000b
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 1
numChildren = 0
[zk: localhost:2181(CONNECTED) 6]

（3）在a節點下面新增節點c，pZxid、cversion、numChildren 發生改變

[zk: localhost:2181(CONNECTED) 6] create /a/c 'c'
Created /a/c
[zk: localhost:2181(CONNECTED) 7] stat /a
cZxid = 0x200000009
ctime = Thu Mar 22 13:07:19 CST 2018
mZxid = 0x20000000a
mtime = Thu Mar 22 13:12:53 CST 2018 pZxid = 0x20000000c cversion = 1
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3 numChildren = 1
[zk: localhost:2181(CONNECTED) 8]

（4）ephemeralOwner 持久性的節點信息是0x0臨時的幾點信息是本次會話的sessionid，如圖

(5) 將leader幹掉，此時第二臺機器成爲leader，從新建立一個文件y，此時發現czxid的前3位和以前發生變化，說明換了leader

[zk: localhost:2181(CONNECTED) 0] create /y 'yy'
Created /y
[zk: localhost:2181(CONNECTED) 2] stat /y
cZxid = 0x300000003
ctime = Thu Mar 22 13:25:51 CST 2018
mZxid = 0x300000003
mtime = Thu Mar 22 13:25:51 CST 2018
pZxid = 0x300000003
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 2
numChildren = 0
[zk: localhost:2181(CONNECTED) 3]