zookeeper学习之集群环境搭建

一、安装环境

zookeeper：3.4.6

JDK：1.8

linux：centos6.5  64位

主机：

server0:192.168.0.224
server1:192.168.0.225
server2:192.168.0.226

二、安装

1、将ZK解压到/usr/local/zookeeper下
2、修改配置文件（配置环境变量） /etc/profile
JAVA_HOME=/usr/local/jdk1.8
ZOOKEEPER_HOME=/usr/local/zookeeper
PATH=$JAVA_HOME/bin:$ZOOKEEPER_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME ZOOKEEPER_HOME PATH CLASSPATH 
3、source /etc/profile 让配置生效
4、修改zk的配置文件名 /usr/local/zookeeper/conf/zoo_sample.cfg
   [root@rocketmq-nameserver1 conf]# mv zoo_sample.cfg zoo.cfg
5、修改配置 zoo.cfg
#存放数据的路径
dataDir=/usr/local/zookeeper/data
6、在/usr/local/zookeeper 下 创建 myid文件
server0:192.168.0.224     myid=0
server1:192.168.0.225     myid=1
server2:192.168.0.226     myid=2
7、zoo.cfg 配置集群节点   在该文件末尾添加
server.0=192.168.0.224:2888:3888
server.1=192.168.0.225:2888:3888
server.2=192.168.0.226:2888:3888
 
8、zk的启动
对于配置环境变量的启动 ：
zkServer.sh start
没有配置环境变量 可以在 zk 的bin 目录中启动
[root@rocketmq-nameserver1 bin]# ./zkServer.sh   启动这三台服务器

1、启动异常：

[root@localhost bin]# ./zkServer.sh status
JMX enabled by default
Using config: /usr/local/zookeeper/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.

如果遇到该情况试着开启2181端口（或者关闭防火墙）

 /sbin/iptables -I INPUT -p tcp --dport 2181 -j ACCEPT   写入修改
 /etc/init.d/iptables save   保存修改
 service iptables restart    重启防火墙，修改生效
 
service iptables stop  关闭防火墙

2、查看是否启动成功：三个服务器分别查看

[root@localhost bin]# ./zkServer.sh status
JMX enabled by default
Using config: /usr/local/zookeeper/bin/../conf/zoo.cfg
Mode: follower

三、配置文件

# The number of milliseconds of each tick
#tickTime这个时间是作为zookeeper服务器之间或客户端与服务器之间维持心跳的时间间隔,也就是说每个tickTime时间就会发送一个心跳。
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
 
#initLimit这个配置项是用来配置zookeeper接受客户端（这里所说的客户端不是用户连接zookeeper服务器的客户端,而是zookeeper服务器集群中连接到leader的follower 服务器）
初始化连接时最长能忍受多少个心跳时间间隔数。
#当已经超过10个心跳的时间（也就是tickTime）长度后 zookeeper 服务器还没有收到客户端的返回信息,那么表明这个客户端连接失败。总的时间长度就是 10*2000=20秒。
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
#syncLimit这个配置项标识leader与follower之间发送消息,请求和应答时间长度,最长不能超过多少个tickTime的时间长度,总的时间长度就是5*2000=10秒。
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
#dataDir顾名思义就是zookeeper保存数据的目录,默认情况下zookeeper将写数据的日志文件也保存在这个目录里；
dataDir=/usr/local/zookeeper/data
# the port at which the clients will connect
#clientPort这个端口就是客户端连接Zookeeper服务器的端口,Zookeeper会监听这个端口接受客户端的访问请求；
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
#server.A=B:C:D中的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，C第一个端口用来集群成员的信息交换,表示这个服务器与集群中的leader服务器交换信息的端口，
D是在leader挂掉时专门用来进行选举leader所用的端口。
server.0=192.168.0.224:2888:3888
server.1=192.168.0.225:2888:3888
server.2=192.168.0.226:2888:3888

日志文件配置：cat /usr/local/zookeeper/bin/zkEnv.sh

ZOOBINDIR="${ZOOBINDIR:-/usr/bin}"
ZOOKEEPER_PREFIX="${ZOOBINDIR}/.."
 
if [ "x$ZOOCFGDIR" = "x" ]
then
  if [ -e "${ZOOKEEPER_PREFIX}/conf" ]; then
    ZOOCFGDIR="$ZOOBINDIR/../conf"
  else
    ZOOCFGDIR="$ZOOBINDIR/../etc/zookeeper"
  fi
fi
 
if [ -f "${ZOOCFGDIR}/zookeeper-env.sh" ]; then
  . "${ZOOCFGDIR}/zookeeper-env.sh"
fi
 
if [ "x$ZOOCFG" = "x" ]
then
    ZOOCFG="zoo.cfg"
fi
 
ZOOCFG="$ZOOCFGDIR/$ZOOCFG"
 
if [ -f "$ZOOCFGDIR/java.env" ]
then
    . "$ZOOCFGDIR/java.env"
fi
 
if [ "x${ZOO_LOG_DIR}" = "x" ]
then
    ZOO_LOG_DIR="/usr/local/zookeeper/logs"
fi
 
if [ "x${ZOO_LOG4J_PROP}" = "x" ]
then
    ZOO_LOG4J_PROP="INFO,CONSOLE"

四、常用命令

1、登录服务器  ：zkCli.sh -server localhost:2181

2、查看帮助  help：

[zk: 192.168.1.13:2181(CONNECTED) 0] help
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

3、查看更目录的节点：

[zk: 192.168.1.13:2181(CONNECTED) 1] ls /
[zookeeper]

4、创建节点： 创建一个新的Znode节点"zkTest"，以及和它相关内容myData，

[zk: 192.168.1.13:2181(CONNECTED) 2] create /zkTest myData
Created /zkTest

5、查看节点中的内容

[zk: 192.168.1.13:2181(CONNECTED) 4] get /zkTest
myData
cZxid = 0x300000002
ctime = Wed Aug 16 19:48:01 CST 2017
mZxid = 0x300000002
mtime = Wed Aug 16 19:48:01 CST 2017
pZxid = 0x300000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 6
numChildren = 0

6、修改节点内容

[zk: 192.168.1.13:2181(CONNECTED) 5] set /zkTest testSet
cZxid = 0x300000002
ctime = Wed Aug 16 19:48:01 CST 2017
mZxid = 0x300000003
mtime = Wed Aug 16 19:52:22 CST 2017
pZxid = 0x300000002
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0

7、删除节点

[zk: 192.168.1.13:2181(CONNECTED) 7] delete /zkTest
[zk: 192.168.1.13:2181(CONNECTED) 9] ls /
[zookeeper]