centos7 新安装基础配置

Posted 2020-10-04

1）关闭selinux

 使用getenforce 可以查看selinux的状态    

[[email protected] ~]$ getenforce

Enforcing

    

或者使用sestatus 

[[email protected] ~]# sestatus

SELinux status:                 enabled

SELinuxfs mount:                /sys/fs/selinux

SELinux root directory:         /etc/selinux

Loaded policy name:             targeted

Current mode:                   permissive

Mode from config file:          enforcing

Policy MLS status:              enabled

Policy deny_unknown status:     allowed

Max kernel policy version:      28

使用setenforce 0临时关闭selinux（为宽容模式Permissive）

[[email protected] ~]# setenforce 0

[[email protected] ~]# getenforce

Permissive

要永久关闭操作如下（红色为修改部分）

[[email protected] ~]# vi /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=disabled

# SELINUXTYPE= can take one of three two values:

#     targeted - Targeted processes are protected,

#     minimum - Modification of targeted policy. Only selected processes are protected.

#     mls - Multi Level Security protection.

SELINUXTYPE=targeted

注意修改后要重启服务器然后再查看一下状态

[[email protected] ~]$ sestatus

SELinux status:                 disabled

2）关闭防火墙

注意：centos7的防火墙默认使用的是firewalld

临时关闭防火墙

[[email protected] ~]$ systemctl stop firewalld.service

永久关闭防火墙

[[email protected] ~]$ systemctl disable firewalld.service

Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.

查看防火墙的状态

[[email protected] ~]$ firewall-cmd --state

not running

3）基本优化

修改最大打开进程数和最大文件句柄，先使用ulimit命令查看

[[email protected] ~]# ulimit -n

1024

[[email protected] ~]# ulimit -u

3480

修改相关的配置

[[email protected] ~]# vi /etc/security/limits.conf

在最后追加下面几行

* soft nofile 1024000

* hard nofile 1024000

* soft nproc 1024000

* hard nproc 1024000

再修改/etc/security/limits.d下的文件20-nproc.conf (红色为修改项 已修改)

[[email protected] ~]# vi /etc/security/limits.d/20-nproc.conf

# Default limit for number of user‘s processes to prevent

# accidental fork bombs.

# See rhbz #432903 for reasoning.

*          soft    nproc     1024000

*          hard    nproc     1024000

注意：修改完成后重启生效

内核基础优化配置，（暂时不太懂，先直接操作即可）

[[email protected] sysctl.d]# vi /usr/lib/sysctl.d/ 00-system.conf

追加下面的参数

#关闭ipv6

net.ipv6.conf.all.disable_ipv6 = 1

net.ipv6.conf.default.disable_ipv6 = 1

# 避免放大攻击

net.ipv4.icmp_echo_ignore_broadcasts = 1

# 开启恶意icmp错误消息保护

net.ipv4.icmp_ignore_bogus_error_responses = 1

#关闭路由转发

net.ipv4.ip_forward = 0

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

#开启反向路径过滤

net.ipv4.conf.all.rp_filter = 1

net.ipv4.conf.default.rp_filter = 1

#处理无源路由的包

net.ipv4.conf.all.accept_source_route = 0

net.ipv4.conf.default.accept_source_route = 0

#关闭sysrq功能

kernel.sysrq = 0

#core文件名中添加pid作为扩展名

kernel.core_uses_pid = 1

# 开启SYN洪水攻击保护

net.ipv4.tcp_syncookies = 1

#修改消息队列长度

kernel.msgmnb = 65536

kernel.msgmax = 65536

#设置最大内存共享段大小bytes

kernel.shmmax = 68719476736

kernel.shmall = 4294967296

#timewait的数量，默认180000

net.ipv4.tcp_max_tw_buckets = 6000

net.ipv4.tcp_sack = 1

net.ipv4.tcp_window_scaling = 1

net.ipv4.tcp_rmem = 4096 87380 4194304

net.ipv4.tcp_wmem = 4096 16384 4194304

net.core.wmem_default = 8388608

net.core.rmem_default = 8388608

net.core.rmem_max = 16777216

net.core.wmem_max = 16777216

#每个网络接口接收数据包的速率比内核处理这些包的速率快时，允许送到队列的数据包的最大数目

net.core.netdev_max_backlog = 262144

#限制仅仅是为了防止简单的DoS 攻击

net.ipv4.tcp_max_orphans = 3276800

#未收到客户端确认信息的连接请求的最大值

net.ipv4.tcp_max_syn_backlog = 262144

net.ipv4.tcp_timestamps = 0

#内核放弃建立连接之前发送SYNACK 包的数量

net.ipv4.tcp_synack_retries = 1

#内核放弃建立连接之前发送SYN 包的数量

net.ipv4.tcp_syn_retries = 1

#启用timewait 快速回收

net.ipv4.tcp_tw_recycle = 1

#开启重用。允许将TIME-WAIT sockets 重新用于新的TCP 连接

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_mem = 94500000 915000000 927000000

net.ipv4.tcp_fin_timeout = 1

#当keepalive 起用的时候，TCP 发送keepalive 消息的频度。缺省是2 小时

net.ipv4.tcp_keepalive_time = 30

#允许系统打开的端口范围

net.ipv4.ip_local_port_range = 1024 65000

#修改防火墙表大小，默认65536

#net.netfilter.nf_conntrack_max=655350

#net.netfilter.nf_conntrack_tcp_timeout_established=1200

# 确保无人能修改路由表

net.ipv4.conf.all.accept_redirects = 0

net.ipv4.conf.default.accept_redirects = 0

net.ipv4.conf.all.secure_redirects = 0

net.ipv4.conf.default.secure_redirects = 0

使其生效

[[email protected] sysctl.d]# sysctl -p

4）简化开机服务

这个暂时先不搞

5）做个快捷设置网络脚本

先配置下centos7的网络  首先使用ip命令查看下状态

[[email protected] network-scripts]# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1

    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

    inet 127.0.0.1/8 scope host lo

       valid_lft forever preferred_lft forever

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

    link/ether 00:0c:29:36:ff:fd brd ff:ff:ff:ff:ff:ff

    inet 192.168.0.101/24 brd 192.168.0.255 scope global ens33

       valid_lft forever preferred_lft forever

3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000

    link/ether 52:54:00:bd:63:40 brd ff:ff:ff:ff:ff:ff

    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0

       valid_lft forever preferred_lft forever

4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000

    link/ether 52:54:00:bd:63:40 brd ff:ff:ff:ff:ff:ff

上面出现了3和4.这个我不知道是怎么回事，网上查了下，有干掉的办法，贴出来如下

怎么多出来3和4，virbr0这个东西出现了，上网一查，原来是做虚拟机网桥的。难怪防火墙又是添加对virbr0的NAT规则，又是添加转发规则的。 网上很多说卸载了就好，yum remove libvirt，很遗憾，卸载了也没有用。 还有说改rhnplugin.conf文件的，我在/etc/yum/plugincon.d/就没找到这个文件，也许是centos7的原因吧。反正是搞不定。 查来查去，还是有人搞定的。 [[email protected] protected.d]# brctl show bridge name    bridge id        STP enabled    interfaces virbr0        8000.525400bd6340    yes        virbr0-nic 查看果然有网桥存在，竟然还支持STP，有鸡毛用啊。 [[email protected] protected.d]# virsh net-list  Name                 State      Autostart     Persistent ----------------------------------------------------------  default              active     yes           yes 列表一下看看，还是自动启动的，真烦人。 [[email protected] protected.d]# virsh net-destroy default Network default destroyed 默认强制停止 [[email protected] protected.d]# virsh net-undefine default Network default has been undefined 默认为未定义 [[email protected] protected.d]# systemctl restart  libvirtd.service 不过这个命令真不好，啥提示都没，还不如用service libvirtd restart，起码给点反应，虽然也没啥用。 [[email protected] protected.d]# virsh net-list  Name                 State      Autostart     Persistent ---------------------------------------------------------- [[email protected] protected.d]# brctl show bridge name    bridge id        STP enabled    interfaces [[email protected] protected.d]# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo        valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000     link/ether 00:0c:29:36:ff:fd brd ff:ff:ff:ff:ff:ff     inet 192.168.0.10/24 brd 192.168.0.255 scope global ens33        valid_lft forever preferred_lft forever [[email protected] protected.d]# ^C 在用virsh net-list看看，没啥了 brctl show也没啥了 ip add也没有多出来的两个网卡了

到这里看起来就正常多了，最后配置下

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

TYPE="Ethernet"

BOOTPROTO=static

DEFROUTE="yes"

IPV4_FAILURE_FATAL="no"

IPV6INIT="yes"

IPV6_AUTOCONF="yes"

IPV6_DEFROUTE="yes"

IPV6_FAILURE_FATAL="no"

IPV6_ADDR_GEN_MODE="stable-privacy"

NAME=ens33

UUID="06ce2307-5a1c-4624-8a7a-f1ba1fd87458"

DEVICE=ens33

ONBOOT="yes"

DNS1=202.102.224.68

IPADDR0=192.168.0.10

PREFIX=24

GATEWAY0=192.168.0.1

IPV6_PEERDNS=yes

IPV6_PEERROUTES=yes

IPV6_PRIVACY=no

备注：红色字体为修改添加的部分  蓝色字体是不能随便修改的部分，曾试过修改后无法重启网络，而且在当前文件夹下如果有第三个网络配置文件也是无法重启的。

重启网络（有几种重启的方法，centos7推荐使用的是下面的方式，而且使用久方式可能会给你转发请求到此命令   无返回值即为最好的结果）

[[email protected] network-scripts]# systemctl restart network.service

[[email protected] network-scripts]#

 基本上完成以上操作既可以正常使用了，我使用此模板作为克隆源，所以写一个简单的脚本来方便的进行ip修改>>>>>

编写脚本：

创建一个脚本目录并创建一个简单的更换ip的脚本

[[email protected] /]# mkdir /home/snail/scripts

[[email protected] /]# cd /home/snail/scripts

[[email protected] scripts]# touch ipcrt:wq

[[email protected] scripts]# chmod +x ipcrt

[[email protected] scripts]# vi ~/.bashrc

# .bashrc

# User specific aliases and functions

alias rm=‘rm -i‘

alias cp=‘cp -i‘

alias mv=‘mv -i‘

# Source global definitions

if [ -f /etc/bashrc ]; then

        . /etc/bashrc

fi

#这里要注意，要把环境变量写入这个文件下，不然重启失效

PATH="/home/snail/scripts:$PATH"

[[email protected] scripts]# ll

total 0

-rwxr-xr-x 1 root root 0 Aug 29 15:42 ip_create.sh

[[email protected] scripts]# vi ipcrt 

没有进行参数校验，需要注意，参数必须写正确，否则会出问题。

#! /bin/sh

sed -i ‘/IPADDR.*/d‘ /etc/sysconfig/network-scripts/ifcfg-ens33

echo ‘IPADDR0‘=$1>>/etc/sysconfig/network-scripts/ifcfg-ens33

systemctl restart network.service

改版之后的脚本

[[email protected] scripts]# cat ipcrt

#! /bin/bash

#对参数进行判断

case "$1" in

    --help)

        echo "please enter an IP address !"

        echo "Scope in 192.168.0.10 - 192.168.0.99";;

    *)

        if [[ ${#1} -eq 12 ]];then

            sed -i ‘/IPADDR.*/d‘ /etc/sysconfig/network-scripts/ifcfg-ens33

            echo ‘IPADDR0‘=$1>>/etc/sysconfig/network-scripts/ifcfg-ens33

            systemctl restart network.service

            sleep 1

            echo "ip changed ok!"

        else

            echo "error:input error!"

            echo ‘please enter a "--help" view the help information!‘

        fi

    ;;

esac

创建一个更换主机名的脚本（只适用centos7）

#! /bin/bash

hostnamectl set-hostname $1

sed -i ‘/127.0.0.1*/d‘ /etc/hosts

echo "127.0.0.1   " $1  $1 >>/etc/hosts

6）更换yum源

默认使用的是sohu源，看了下里面貌似只支持4,5的版本，所以更改为163的源 地址：mirrors.163.com

[[email protected] ~]# cd /etc/yum.repos.d/

[[email protected] yum.repos.d]# mv CentOS-Base.repo CentOS-Base.repo.old

[[email protected] yum.repos.d]# wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

......

[[email protected] yum.repos.d]# mv CentOS7-Base-163.repo CentOS-Base.repo

[[email protected] yum.repos.d]# yum clean all

[[email protected] yum.repos.d]# yum makecache

7）时间同步

 

查看系统时间

[[email protected] ~]$ date  

Mon Aug 28 23:05:20 PDT 2017

查看时区并修改

[[email protected] ~]# date -R                         （方法1）

Mon, 28 Aug 2017 23:12:35 -0700

[[email protected] ~]# date +%z                        （方法2）

-0700

[[email protected] ~]# cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

cp: overwrite ‘/etc/localtime’? y

安装时间同步工具

[[email protected] ~]# yum -y install ntp ntpdate

同步时间

[[email protected] ~]# ntpdate cn.pool.ntp.org

设置定时更新时间任务

[[email protected] ~]# echo ‘*/10 * * * * /usr/sbin/ntpdate time.nist.gov >/dev/null 2>&1‘ >>/var/spool/cron/root

本文出自 “不懈的蜗牛” 博客，请务必保留此出处http://songxiao.blog.51cto.com/12183698/1961175