Linux Zookeeper安装

时间 2021-02-14

标签 html java node linux web 算法 apache vim api bash 栏目 Linux 繁體版

原文原文链接

zookeeper简介

ZooKeeper是一个分布式的，开放源码的分布式应用程序协调服务，是Google的Chubby一个开源的实现，是Hadoop和Hbase的重要组件。它是一个为分布式应用提供一致性服务的软件，提供的功能包括：配置维护、名字服务、分布式同步、组服务等。
ZooKeeper的目标就是封装好复杂易出错的关键服务，将简单易用的接口和性能高效、功能稳定的系统提供给用户。
ZooKeeper包含一个简单的原语集，提供Java和C的接口。ZooKeeper源代码中，提供了分布式独享锁、选举、队列的接口，代码在zookeeper-x.x.x\src\recipes。其中分布锁和队列有Java和C两个版本，选举只有Java版本。html

zookeeper的原理

ZooKeeper是以Fast Paxos算法为基础的，paxos算法存在活锁的问题，即当有多个proposer交错提交时，有可能互相排斥致使没有一个proposer能提交成功，而Fast Paxos做了一些优化，经过选举产生一个leader，只有leader才能提交propose。=。所以要想弄懂ZooKeeper首先得对Fast Paxos有所了解。java

ZooKeeper的基本运转流程：node

选举Leader。
同步数据。
选举Leader过程当中算法有不少，但要达到的选举标准是一致的。
Leader要具备最高的zxid。
集群中大多数的机器获得响应并follow选出的Leader

zookeeper的特色

在Zookeeper中，znode是一个跟Unix文件系统路径类似的节点，能够往这个节点存储或获取数据。若是在建立znode时Flag设置为EPHEMERAL，那么当建立这个znode的节点和Zookeeper失去链接后，这个znode将再也不存在在Zookeeper里，Zookeeper使用Watcher察觉事件信息。当客户端接收到事件信息，好比链接超时、节点数据改变、子节点改变，能够调用相应的行为来处理数据。Zookeeper的Wiki页面展现了如何使用Zookeeper来处理事件通知，队列，优先队列，锁，共享锁，可撤销的共享锁，两阶段提交。那么Zookeeper能做什么事情呢，简单的例子：假设咱们有20个搜索引擎的服务器(每一个负责总索引中的一部分的搜索任务)和一个总服务器(负责向这20个搜索引擎的服务器发出搜索请求并合并结果集)，一个备用的总服务器(负责当总服务器宕机时替换总服务器)，一个web的cgi(向总服务器发出搜索请求)。搜索引擎的服务器中的15个服务器提供搜索服务，5个服务器正在生成索引。这20个搜索引擎的服务器常常要让正在提供搜索服务的服务器中止提供服务开始生成索引，或生成索引的服务器已经把索引生成完成能够搜索提供服务了。使用Zookeeper能够保证总服务器自动感知有多少提供搜索引擎的服务器并向这些服务器发出搜索请求，当总服务器宕机时自动启用备用的总服务器。linux

安装

准备工做
在安装zookeeper以前咱们要确保本身主机上已经有了Java环境，建议安装Oracle JDK8.xweb

环境	版本
RHEL/CentOS	7.x
Java	8.x
Zookeeper	3.4.x

# 检查java环境
[thinktik@localhost ~]$ java -version
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
[thinktik@localhost ~]$ ls
apache-maven-3.6.0-bin.tar.gz  httpd-2.4.37.tar.gz         jenkins.war      sonarqube-6.7.5.tar
httpd                          java8                       maven            zookeeper-3.4.13.tar.gz
httpd-2.4.37                   jdk-8u191-linux-x64.tar.gz  sonarqube-6.7.5
# 解压
[thinktik@localhost ~]$ tar -zxvf zookeeper-3.4.13.tar.gz

[thinktik@localhost ~]$ ls
apache-maven-3.6.0-bin.tar.gz  httpd-2.4.37.tar.gz         jenkins.war      sonarqube-6.7.5.tar
httpd                          java8                       maven            zookeeper-3.4.13
httpd-2.4.37                   jdk-8u191-linux-x64.tar.gz  sonarqube-6.7.5  zookeeper-3.4.13.tar.gz
[thinktik@localhost ~]$ cd zookeeper-3.4.13
[thinktik@localhost zookeeper-3.4.13]$ ls
bin        dist-maven       lib          README_packaging.txt  zookeeper-3.4.13.jar.asc
build.xml  docs             LICENSE.txt  recipes               zookeeper-3.4.13.jar.md5
conf       ivysettings.xml  NOTICE.txt   src                   zookeeper-3.4.13.jar.sha1
contrib    ivy.xml          README.md    zookeeper-3.4.13.jar
# 建立data文件夹保持数据
[thinktik@localhost zookeeper-3.4.13]$ mkdir data
# 建立logs文件夹保存日志
[thinktik@localhost zookeeper-3.4.13]$ mkdir logs
[thinktik@localhost zookeeper-3.4.13]$ pwd
/home/thinktik/zookeeper-3.4.13
[thinktik@localhost zookeeper-3.4.13]$ cd conf/
[thinktik@localhost conf]$ ls
configuration.xsl  log4j.properties  zoo_sample.cfg
# 将样例配置文件复制一份为zoo.cfg
[thinktik@localhost conf]$ cp zoo_sample.cfg zoo.cfg 
# 修改配置文件
[thinktik@localhost conf]$ vim zoo.cfg

配置文件参考（这里我将dataDir和dataLogDir路径改成了我刚才建立文件夹）
算法

单机版启动apache

[thinktik@localhost conf]$ cd ..
[thinktik@localhost zookeeper-3.4.13]$ ls
bin        dist-maven       LICENSE.txt           recipes                   zookeeper-3.4.13.jar.sha1
build.xml  docs             logs                  src
conf       ivysettings.xml  NOTICE.txt            zookeeper-3.4.13.jar
contrib    ivy.xml          README.md             zookeeper-3.4.13.jar.asc
data       lib              README_packaging.txt  zookeeper-3.4.13.jar.md5
[thinktik@localhost zookeeper-3.4.13]$ cd bin/
[thinktik@localhost bin]$ ls
README.txt    zkCli.cmd  zkEnv.cmd  zkServer.cmd  zkTxnLogToolkit.cmd
zkCleanup.sh  zkCli.sh   zkEnv.sh   zkServer.sh   zkTxnLogToolkit.sh
# 启动
[thinktik@localhost bin]$ ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
# 状态查询为正在运行，单例模式
[thinktik@localhost bin]$ ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Mode: standalone

# 检查端口监听ok
[thinktik@localhost bin]$ netstat -nlp | grep 2181
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp6       0      0 :::2181                 :::*                    LISTEN      1958/java  
# 检查运行线程ok
[thinktik@localhost bin]$ ps -ef |grep zoo
thinktik  1958     1  0 11:17 pts/0    00:00:00 java -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -cp /home/thinktik/zookeeper-3.4.13/bin/../build/classes:/home/thinktik/zookeeper-3.4.13/bin/../build/lib/*.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/slf4j-log4j12-1.7.25.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/slf4j-api-1.7.25.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/netty-3.10.6.Final.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/log4j-1.2.17.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/jline-0.9.94.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/audience-annotations-0.5.0.jar:/home/thinktik/zookeeper-3.4.13/bin/../zookeeper-3.4.13.jar:/home/thinktik/zookeeper-3.4.13/bin/../src/java/lib/*.jar:/home/thinktik/zookeeper-3.4.13/bin/../conf: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
thinktik  1978  1890  0 11:19 pts/0    00:00:00 grep --color=auto zoo
# 客户端链接ok
[thinktik@localhost bin]$ ./zkCli.sh 
Connecting to localhost:2181
2018-11-11 11:48:15,274 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.13-2d71af4dbe22557fda74f9a9b4309b15a7487f03, built on 06/29/2018 04:05 GMT
2018-11-11 11:48:15,277 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=localhost
2018-11-11 11:48:15,277 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.8.0_191
2018-11-11 11:48:15,279 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Oracle Corporation
2018-11-11 11:48:15,279 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=/home/thinktik/java8/jre
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=/home/thinktik/zookeeper-3.4.13/bin/../build/classes:/home/thinktik/zookeeper-3.4.13/bin/../build/lib/*.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/slf4j-log4j12-1.7.25.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/slf4j-api-1.7.25.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/netty-3.10.6.Final.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/log4j-1.2.17.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/jline-0.9.94.jar:/home/thinktik/zookeeper-3.4.13/bin/../lib/audience-annotations-0.5.0.jar:/home/thinktik/zookeeper-3.4.13/bin/../zookeeper-3.4.13.jar:/home/thinktik/zookeeper-3.4.13/bin/../src/java/lib/*.jar:/home/thinktik/zookeeper-3.4.13/bin/../conf:
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=/tmp
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Linux
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=amd64
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=3.10.0-862.el7.x86_64
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=thinktik
2018-11-11 11:48:15,280 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/home/thinktik
2018-11-11 11:48:15,281 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/home/thinktik/zookeeper-3.4.13/bin
2018-11-11 11:48:15,282 [myid:] - INFO  [main:ZooKeeper@442] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@25f38edc
2018-11-11 11:48:15,320 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1029] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
Welcome to ZooKeeper!
JLine support is enabled
2018-11-11 11:48:15,489 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@879] - Socket connection established to localhost/127.0.0.1:2181, initiating session
[zk: localhost:2181(CONNECTING) 0] 2018-11-11 11:48:15,829 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1303] - Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x100003dc9010000, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null

[zk: localhost:2181(CONNECTED) 0] 
[zk: localhost:2181(CONNECTED) 0]

这里Zookeeper单机版就安装完成了vim

Zookeeper集群

单机模式的zk进程虽然便于开发与测试，但并不适合在生产环境使用。在生产环境下，咱们须要使用集群模式来对zk进行部署。api

注意在集群模式下，建议至少部署3个zk进程，或者部署奇数个zk进程。若是只部署2个zk进程，当其中一个zk进程挂掉后，剩下的一个进程并不能构成一个quorum的大多数。所以，部署2个进程甚至比单机模式更不可靠，由于2个进程其中一个不可用的可能性比一个进程不可用的可能性还大。bash

我继续按单机版的安装方式在例外的两个虚拟机上安装2个zookeeper，并互相开放防火墙。

主机	IP
CentOS01	192.168.50.186
CentOS02	192.168.50.164
CentOS03	192.168.50.30

关键点是你将全部的zookeeper节点都写在配置文件里面去，并在这些主机上开发端口。我开的是2181，2888，3888三个端口，3个主机都开。

个人集群配置添加以下3个节点配置（记得Linux打开端口）：

server.1=192.168.50.186:2888:3888
server.2=192.168.50.164:2888:3888
server.3=192.168.50.30:2888:3888

同时不要忘了在这3个主机安装的zookeeper的dataDir创建各自的myid文件并填入本身的id.

# 我以3号zookeeper为例
[thinktik@localhost zookeeper]$ cd data/
[thinktik@localhost data]$ pwd
/home/thinktik/zookeeper/data
# 这个zookeeper配置dataDir下面我创建了myid
[thinktik@localhost data]$ ls
myid  version-2  zookeeper_server.pid
# myid里面写上了它的id，id好与server.x的x对应。例如三号机是server.3=192.168.50.30:2888:3888那么myid里面填3
[thinktik@localhost data]$ cat myid 
3

启动集群，这里3个zookeeper随便启动就能够，没什么前后顺序，每一个zookeeper启动后会找本身其余节点的。

# 1号zookeeper我先启动。 2,3号我接着起
[thinktik@localhost bin]$ ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[thinktik@localhost bin]$ ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.
[thinktik@localhost bin]$ vim ../conf/zoo.cfg 
[thinktik@localhost bin]$ vim ../data/myid 
[thinktik@localhost bin]$ ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

# 1，2，3都起后查看状态，1号成了leader
[thinktik@localhost bin]$ ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper-3.4.13/bin/../conf/zoo.cfg
Mode: leader

# 启动2，3号
[thinktik@localhost bin]$ ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[thinktik@localhost bin]$ vim ../data/myid 
bash: vim: command not found
[thinktik@localhost bin]$ vi ../data/myid 
[thinktik@localhost bin]$ ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

# 1，2，3都起后查看状态，2,3号成了leader
[thinktik@localhost bin]$ ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/thinktik/zookeeper/bin/../conf/zoo.cfg
Mode: follower

验证下集群的功能

leader：

[zk: localhost:2181(CONNECTED) 0] ls/
ZooKeeper -server host:port cmd args
    stat path [watch]
    set path data [version]
    ls path [watch]
    delquota [-n|-b] path
    ls2 path [watch]
    setAcl path acl
    setquota -n|-b val path
    history 
    redo cmdno
    printwatches on|off
    delete path [version]
    sync path
    listquota path
    rmr path
    get path [watch]
    create [-s] [-e] path data acl
    addauth scheme auth
    quit 
    getAcl path
    close 
    connect host:port
# 建立节点
[zk: localhost:2181(CONNECTED) 1] create /testNode '测试'
Created /testNode
# 节点已建立
[zk: localhost:2181(CONNECTED) 2] ls /
[zookeeper, testNode]

follower

# 查询节点，发现leader的节点已经同步，一致性没问题
[zk: localhost:2181(CONNECTED) 1] ls /
[zookeeper, testNode]
# 查看这个节点的内容，也没毛病
[zk: localhost:2181(CONNECTED) 3] get /testNode
测试
cZxid = 0x100000002
ctime = Sun Nov 11 13:28:20 CST 2018
mZxid = 0x100000002
mtime = Sun Nov 11 13:28:20 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 6
numChildren = 0

这里基本集群就ok了。

本文原创连接：Linux Zookeeper安装

本文除了阅读了Zookeeper官方文档还参考的其余人写的文章：