# 集群搭建概述与JDK安装

## Zookeeper集群搭建

zk集群，主从节点，心跳机制（选举模式）

![](/files/-LfnTHUOVwwv-ubwxu3l)

1.选举模式必须为奇数节点，最少为3节点

2.xx挂掉，从新选举一个新的节点zz为mater

3.当xx节点恢复，不会抢占master，以slave角色。

### Zookeeper集群搭建注意点

* 配置数据文件myid  1/2/3 对应server.1/2/3
* 通过\`./zkCli.sh -server \[ip]:\[port] 检测集群是否配置成功

## JDK安装

环境要求:必须要有jdk环境,如：jdk1.8

下载地址：

<http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz>

配置：

```
vi /etc/profile
export JAVA_HOME=/usr/jdk8
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin
```

运行以下使配置生效

```
source /etc/profile
```


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