1 简介
在大数据集群部署过程中，各集群节点的服务器时间可能不一致，会导致数据出错，这里使用syncDate进行批量时间同步。
2 配置集群hostname
2.1 配置hostname文件
1 服务器hadoop01
[root@localhost ~]# echo hostname1 > /etc/hostname
hostname hadoop01
2 服务器hadoop02
[root@localhost ~]# echo hadoop02 > /etc/hostname
hostname hadoop02
3 服务器hadoop03
[root@localhost ~]# echo hadoop03 > /etc/hostname
hostname hadoop03
4 服务器hadoop04
[root@localhost ~]# echo hadoop04 > /etc/hostname
hostname hadoop04
2.2 配置hosts文件
同步脚本的那台机器上，现在是hadoop01
192.168.85.101 hadoop01
192.168.85.102 hadoop02
192.168.85.103 hadoop03
192.168.85.104 hadoop04
192.168.85.105 hadoop05
3 配置免密登录
3.1 生成rsa密钥
使用命令ssh-keygen 生成rsa密钥，配置信息直接回车即可, 生成的密钥默认在当前用户主目录的.ssh目录下。
密钥文件有两个：
- id_rsa 存放着私钥
- id_rsa.pub 存放着公钥
[root@localhost ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:fX0pdntsAyRWTvjuoSG+VFu/vsfFpRypBi2Z5iRY8ok root@localhost.localdomain
The key's randomart image is:
+---[RSA 2048]----+
| .o |
| . . .+ |
| * . *.o . |
| E +.O +oo o|
| S=.+oB.*o|
| .oo*oBo+|
| ...o+ .==|
| .. . . .*|
| .. .+o|
+----[SHA256]-----+
[root@localhost ~]#
3.2 同步公钥到其他服务器
3.2.1 安装rsync
[root@localhost ~]# yum install -y rsync
3.2.1 同步公钥
[root@localhost ~]# cp id_rsa.pub authorized_keys
[root@localhost ~]# rsync authorized_keys root@hadoop02:/root/.ssh/
[root@localhost ~]# rsync authorized_keys root@hadoop03:/root/.ssh/
[root@localhost ~]# rsync authorized_keys root@hadoop04:/root/.ssh/
3.3 免密登录测试
无需输入密码，代表密码登录配置成功
[root@localhost ~]# root@hadoop02
4 syncDate脚本使用
用户主目录的bin目录添加
pwd查看当前目录，用户登录进去的初始目录，一般为家目录
4.1 创建脚本
#!/bin/bash
# 循环
for host in 01 02 03 04; do
echo ------------------- hadoop$host --------------
ssh hadoop$host ' ntpdate ntp.sjtu.edu.cn '
nowTime=`date "+%Y-%m-%d %H:%M:%S"`
echo "hadoop$host 同步时间成功，当前时间：" $nowTime
done
4.2 测试脚本
[root@localhost ~]# syncDate
----------------- hadoop01 同步时间成功，当前时间 --------------
----------------- hadoop02 同步时间成功，当前时间 --------------
----------------- hadoop03 同步时间成功，当前时间 --------------
----------------- hadoop04 同步时间成功，当前时间 --------------
----------------- hadoop05 同步时间成功，当前时间 --------------
