CentOS 6.x 初始安装基本优化操作
本文件是采用的模板是 centos 6.x，相较于 centos 5.x 与 centos 7.x 系列有些区别，不能一概而论。
1. 测试环境
- MacBook Pro 15-inch i7 8GB
- VMware Fushion 8 Pro
- CentOS-6.7-x86_64-minimal.iso
2. 默认网卡开机未设定自启动
很多初学者，在安装系统的时候，碰到的第一个问题就是不能上网，所以有些同学就担心是不是需要去安装网卡驱动，其实这样想就把问题复杂化了，如果你在实体机安装 Linux 的系统时，可能会碰到网卡驱动不上导致无法上网的问题，这个时候是需要自行安装驱动的，但是我们使用的 VMware 的一款虚拟化工具，所以网卡驱动基本就不用考虑，原因是因为我们没有把网卡设置为开机自启动，下面讲如何开启网卡，并设定为开机自启动。
[root@vm02 ~]# ifup eth0
Determining IP information for eth0... done.
[root@vm02 ~]#
[root@vm02 ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:B9:60:D8
inet addr:172.16.102.129 Bcast:172.16.102.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:feb9:60d8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:127 errors:0 dropped:0 overruns:0 frame:0
TX packets:85 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:14010 (13.6 KiB) TX bytes:11410 (11.1 KiB)
[root@vm02 ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
HWADDR=00:0C:29:B9:60:D8
TYPE=Ethernet
UUID=7ad636ff-78d9-4afa-9886-706b1de236a8
ONBOOT=no // 默认是no，修改为yes
NM_CONTROLLED=yes
BOOTPROTO=dhcp
3. 增加第三方 Yum 源
CentOS 系统内置的官方源软件更新较慢，而且缺少一些常用软件包，建议安装 epel 源，EPEL 是 Extra Packages for Enterprise Linux 的缩写（EPEL），是用于 Fedora-based Red Hat Enterprise Linux (RHEL) 的一个高质量软件源，所以同时也适用于 CentOS 或者 Scientific Linux 等发行版。
a. 因为我们使用的是 minimal 版本的 ISO 安装，所以系统默认没有 wget，我们可以直接用 yum 安装：[wget 是 Linux 常用的命令行下载工具]
[root@vm02 ~]# yum install -y wget
Loaded plugins: fastestmirror
Setting up Install Process
base | 3.7 kB 00:00
base/primary_db | 4.6 MB 00:32
extras | 3.4 kB 00:00
extras/primary_db | 34 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 4.0 MB 01:05
Resolving Dependencies
--> Running transaction check
---> Package wget.x86_64 0:1.12-5.el6_6.1 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
wget x86_64 1.12-5.el6_6.1 base 483 k
Transaction Summary
================================================================================
Install 1 Package(s)
Total download size: 483 k
Installed size: 1.8 M
Downloading Packages:
wget-1.12-5.el6_6.1.x86_64.rpm | 483 kB 00:01
warning: rpmts_HdrFromFdno: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Importing GPG key 0xC105B9DE:
Userid : CentOS-6 Key (CentOS 6 Official Signing Key) <centos-6-key@centos.org>
Package: centos-release-6-7.el6.centos.12.3.x86_64 (@anaconda-CentOS-201508042137.x86_64/6.7)
From : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : wget-1.12-5.el6_6.1.x86_64 1/1
Verifying : wget-1.12-5.el6_6.1.x86_64 1/1
Installed:
wget.x86_64 0:1.12-5.el6_6.1
Complete!
[root@vm02 ~]#
b. 下载并安装 epel 源
不同 CentOS 版本的 epel 下载地址：
- CentOS 5 : https://dl.fedoraproject.org/pub/epel/epel-release-latest-5.noarch.rpm
- CentOS 6 : https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
- CentOS 7 : https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
本次试验用到的 CentOS 6 所以我们下载 epel-release-latest-6.noarch.rpm
[root@vm02 ~]# wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
--2016-03-18 11:47:17-- https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
Resolving dl.fedoraproject.org... 209.132.181.26, 209.132.181.23, 209.132.181.24, ...
Connecting to dl.fedoraproject.org|209.132.181.26|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14540 (14K) [application/x-rpm]
Saving to: “epel-release-latest-6.noarch.rpm”
100%[======================================>] 14,540 69.5K/s in 0.2s
2016-03-18 11:47:25 (69.5 KB/s) - “epel-release-latest-6.noarch.rpm” saved [14540/14540]
[root@vm02 ~]# ls
anaconda-ks.cfg install.log
epel-release-latest-6.noarch.rpm install.log.syslog
4. 安装 vim：Linux 使用最广泛的文件编辑工具
与我们长久使用 Win 环境不同的是，在 Linux 之中，我们接触最多的是 command line，所以熟练一款命令行下的文本编辑工具是一项必备技能，我这里推荐大家：vim。
[root@vm02 ~]# yum install -y vim
Loaded plugins: fastestmirror
Setting up Install Process
Determining fastest mirrors
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package vim-enhanced.x86_64 2:7.4.629-5.el6 will be installed
--> Processing Dependency: vim-common = 2:7.4.629-5.el6 for package: 2:vim-enhanced-7.4.629-5.el6.x86_64
--> Processing Dependency: perl(:MODULE_COMPAT_5.10.1) for package: 2:vim-enhanced-7.4.629-5.el6.x86_64
--> Processing Dependency: libperl.so()(64bit) for package: 2:vim-enhanced-7.4.629-5.el6.x86_64
--> Processing Dependency: libgpm.so.2()(64bit) for package: 2:vim-enhanced-7.4.629-5.el6.x86_64
--> Running transaction check
---> Package gpm-libs.x86_64 0:1.20.6-12.el6 will be installed
---> Package perl.x86_64 4:5.10.1-141.el6_7.1 will be installed
--> Processing Dependency: perl(version) for package: 4:perl-5.10.1-141.el6_7.1.x86_64
--> Processing Dependency: perl(Pod::Simple) for package: 4:perl-5.10.1-141.el6_7.1.x86_64
--> Processing Dependency: perl(Module::Pluggable) for package: 4:perl-5.10.1-141.el6_7.1.x86_64
---> Package perl-libs.x86_64 4:5.10.1-141.el6_7.1 will be installed
---> Package vim-common.x86_64 2:7.4.629-5.el6 will be installed
--> Processing Dependency: vim-filesystem for package: 2:vim-common-7.4.629-5.el6.x86_64
--> Running transaction check
---> Package perl-Module-Pluggable.x86_64 1:3.90-141.el6_7.1 will be installed
---> Package perl-Pod-Simple.x86_64 1:3.13-141.el6_7.1 will be installed
--> Processing Dependency: perl(Pod::Escapes) >= 1.04 for package: 1:perl-Pod-Simple-3.13-141.el6_7.1.x86_64
---> Package perl-version.x86_64 3:0.77-141.el6_7.1 will be installed
---> Package vim-filesystem.x86_64 2:7.4.629-5.el6 will be installed
--> Running transaction check
---> Package perl-Pod-Escapes.x86_64 1:1.04-141.el6_7.1 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
=============================================================================================================================================================================
Package Arch Version Repository Size
=============================================================================================================================================================================
Installing:
vim-enhanced x86_64 2:7.4.629-5.el6 base 1.0 M
Installing for dependencies:
gpm-libs x86_64 1.20.6-12.el6 base 28 k
perl x86_64 4:5.10.1-141.el6_7.1 updates 10 M
perl-Module-Pluggable x86_64 1:3.90-141.el6_7.1 updates 40 k
perl-Pod-Escapes x86_64 1:1.04-141.el6_7.1 updates 33 k
perl-Pod-Simple x86_64 1:3.13-141.el6_7.1 updates 213 k
perl-libs x86_64 4:5.10.1-141.el6_7.1 updates 579 k
perl-version x86_64 3:0.77-141.el6_7.1 updates 52 k
vim-common x86_64 2:7.4.629-5.el6 base 6.7 M
vim-filesystem x86_64 2:7.4.629-5.el6 base 15 k
Transaction Summary
=============================================================================================================================================================================
Install 10 Package(s)
Total download size: 19 M
Installed size: 59 M
Downloading Packages:
(1/10): gpm-libs-1.20.6-12.el6.x86_64.rpm | 28 kB 00:00
(2/10): perl-5.10.1-141.el6_7.1.x86_64.rpm | 10 MB 00:10
(3/10): perl-Module-Pluggable-3.90-141.el6_7.1.x86_64.rpm | 40 kB 00:00
(4/10): perl-Pod-Escapes-1.04-141.el6_7.1.x86_64.rpm | 33 kB 00:00
(5/10): perl-Pod-Simple-3.13-141.el6_7.1.x86_64.rpm | 213 kB 00:00
(6/10): perl-libs-5.10.1-141.el6_7.1.x86_64.rpm | 579 kB 00:00
(7/10): perl-version-0.77-141.el6_7.1.x86_64.rpm | 52 kB 00:00
(8/10): vim-common-7.4.629-5.el6.x86_64.rpm | 6.7 MB 00:07
(9/10): vim-enhanced-7.4.629-5.el6.x86_64.rpm | 1.0 MB 00:01
(10/10): vim-filesystem-7.4.629-5.el6.x86_64.rpm | 15 kB 00:00
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 980 kB/s | 19 MB 00:19
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : 1:perl-Pod-Escapes-1.04-141.el6_7.1.x86_64 1/10
Installing : 1:perl-Module-Pluggable-3.90-141.el6_7.1.x86_64 2/10
Installing : 3:perl-version-0.77-141.el6_7.1.x86_64 3/10
Installing : 4:perl-libs-5.10.1-141.el6_7.1.x86_64 4/10
Installing : 1:perl-Pod-Simple-3.13-141.el6_7.1.x86_64 5/10
Installing : 4:perl-5.10.1-141.el6_7.1.x86_64 6/10
Installing : 2:vim-filesystem-7.4.629-5.el6.x86_64 7/10
Installing : 2:vim-common-7.4.629-5.el6.x86_64 8/10
Installing : gpm-libs-1.20.6-12.el6.x86_64 9/10
Installing : 2:vim-enhanced-7.4.629-5.el6.x86_64 10/10
Verifying : 1:perl-Pod-Simple-3.13-141.el6_7.1.x86_64 1/10
Verifying : 1:perl-Pod-Escapes-1.04-141.el6_7.1.x86_64 2/10
Verifying : gpm-libs-1.20.6-12.el6.x86_64 3/10
Verifying : 2:vim-enhanced-7.4.629-5.el6.x86_64 4/10
Verifying : 2:vim-filesystem-7.4.629-5.el6.x86_64 5/10
Verifying : 1:perl-Module-Pluggable-3.90-141.el6_7.1.x86_64 6/10
Verifying : 2:vim-common-7.4.629-5.el6.x86_64 7/10
Verifying : 3:perl-version-0.77-141.el6_7.1.x86_64 8/10
Verifying : 4:perl-libs-5.10.1-141.el6_7.1.x86_64 9/10
Verifying : 4:perl-5.10.1-141.el6_7.1.x86_64 10/10
Installed:
vim-enhanced.x86_64 2:7.4.629-5.el6
Dependency Installed:
gpm-libs.x86_64 0:1.20.6-12.el6 perl.x86_64 4:5.10.1-141.el6_7.1 perl-Module-Pluggable.x86_64 1:3.90-141.el6_7.1 perl-Pod-Escapes.x86_64 1:1.04-141.el6_7.1
perl-Pod-Simple.x86_64 1:3.13-141.el6_7.1 perl-libs.x86_64 4:5.10.1-141.el6_7.1 perl-version.x86_64 3:0.77-141.el6_7.1 vim-common.x86_64 2:7.4.629-5.el6
vim-filesystem.x86_64 2:7.4.629-5.el6
Complete!
[root@vm02 ~]#
4. 关闭 SELinux
SELinux 主要由美国国家安全局开发，并于 2000 年 12 月 22 日发行给开放源代码的开发社区。SELinux 旨在加强访问控制架构以对付入侵的威胁或任何企图略过安全架构的应用程序，并且从 2.6 版的 Linux 核心就开始集成 SELinux；但是 SELinux 严格的权限控制对于初学者来说并不是非常必要，所以我们建议关闭 SELinux，[其实由于 SELinux 的复杂性，很多运维人员都是选择关闭它，熟悉阿里云 ECS 的同学可能知道，它是默认关闭 SELinux 的，但是我们不建议在生产环境关闭 SELinux。]
SELinux 的配置文件主要由两个：/etc/sysconfig/selinux、 /etc/selinux/config，其实第一个是第二个路径的软链接。
[root@vm02 ~]# vim /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=enforcing
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
SELINUXTYPE=targeted
SELinux 的状态模式：
- enforcing : 强制启用 SELinux
- permissive : 只显示警告讯息以替代强制启用 SELinux
- disabled : 停用 SELinux
Tips: SELinux 的参数只能在重启后生效。
SELinux 常用的两个命令：getenforce setenforce :
- getenforce 获得 SELinux 当前的状态，返回值为如上三种；
- setenforce 临时改变 SELinux 的状态，参数为布尔值，0 是关闭，1 是开启。
Tips: 状态已经为 disabled 时，无法使用 setenforce 1 启用。