CENTOS7系统的初始配置

1.系统时间和时区不一致

1.1 查看系统时间：

  [root@localhost sysconfig]# timedatectl     
  Local time: 一 2017-11-06 21:13:19 CST   
  Universal time: 一 2017-11-06 13:13:19 UTC        
  RTC time: 一 2017-11-06 13:13:19       
  Time zone: Asia/Shanghai (CST, +0800)    
  NTP enabled: noNTP synchronized: no 
  RTC in local TZ: no      
  DST active: n/a

1.2 查看系统时区:

[root@localhost sysconfig]# ls /usr/share/zoneinfo/

Africa      Brazil   Egypt    GB-Eire    HST          Japan      Navajo    posixrules  Turkey     zone1970.tab
America     Canada   Eire     GMT        Iceland      Kwaj

1.3 删除当前系统所处的分区：

[root@localhost sysconfig]# sudo rm /etc/localtime

1.4 从/usr/share/zoneinfo/中创建软连接以替换当前的时区信息，直接选择Universal：:

[root@localhost sysconfig]# sudo ln -s /usr/share/zoneinfo/Universal /etc/localtime

1.5 再次查看系统时间:

[root@localhost sysconfig]# sudo timedatectl

 Local time: 一 2017-11-06 13:14:32 UTC

 Universal time: 一 2017-11-06 13:14:32 UTC

 RTC time: 一 2017-11-06 13:14:32

 Time zone: Universal (UTC, +0000)

 NTP enabled: no

 NTP synchronized: no

 RTC in local TZ: no

 DST active: n/a

2.网络设置

2.1 进入虚拟机设置编辑三个文件（按顺序来）

vim /etc/sysconfig/network

# Created by anaconda

NETWORKING=yes

GATEWAY=192.168.50.2

vim /etc/sysconfig/network-scripts/ifcfg-ens33

TYPE=Ethernet
NAME=ens33
BOOTPROTO=static
NM_CONTROLLED=yes
IPV6INIT=no
ONBOOT=yes
IPADDR=192.168.50.10
PREFIX0=32
NETMASK=255.255.255.0
DNS1=192.168.50.2

vim /etc/resolv.conf

nameserver 192.168.50.2

2.2 重启网络服务

systemctl restart network.service

3. 镜像源切换（阿里）

(1) 备份yum镜像源(cd /etc/yum.repos.d)

[root@slave2 yum.repos.d]#mv /etc/yum.repos.d/CentOS-Base.repo  /etc/yum.repos.d/CentOS-Base.repo.backup

(2) 下载aliyun的yum配置文件到/etc/yum.repos.d

[root@slave2 yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo  

(3) 运行yum生成缓存

[root@slave2 yum.repos.d]# yum makecache

(4)更新系统

[root@slave2 yum.repos.d]# yum -y update

4.卸载CENTOS系统自带的java

查看CentOS自带JDK是否已安装:
yum list installed |grep java
卸载JDK相关文件输入:
yum -y remove java-1.8.0-openjdk*
卸载tzdata-java输入：
yum -y remove tzdata-java.noarch

5.java环境变量配置

vim ~/.bashrc:

# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
JAVA_HOME=/usr/local/src/jdk1.8.0_172
CLASSPATH=.:/usr/local/src/jdk1.8.0_172/bin
PATH=$JAVA_HOME/bin:$PATH
export JAVA_HOME CLASSPATH PATH
# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi