CentOS 7系统优化脚本（centos7网络优化）

作为一名运维工程师，经常会部署各种用途的操作系统，但在这些工作中，我们会发现很多工作其实是重复性的劳动，操作的内容也是大同小异，基于这类情况，我们可以把相同的操作做成统一执行的脚本，不同的东西作为变量手动输入。节约下来的时间不就可以做更多有意义的事情吗？

最近在粉丝有推荐下发现一款比较好用的shell源码，也基于此改编了一下，分享给大家：

主菜单：

二级菜单：

主要实现系统的各类优化，比如常用的修改字符集、关闭selinux、关闭防火墙、安装常用工具和加快ssh登录等功能。

源码如下：

#!/bin/sh

. /etc/rc.d/init.d/functions
export LANG=zh_CN.UTF-8

#一级菜单
menu1()
{
        clear
        cat <<EOF
----------------------------------------
|****   欢迎使用cetnos7.9优化脚本    ****|
|****      博客地址: aaa.al         ****|
----------------------------------------
1. 一键优化
2. 自定义优化
3. 退出
EOF
        read -p "please enter your choice[1-3]:" num1
}

#二级菜单
menu2()
{
 clear
 cat <<EOF
----------------------------------------
|****Please Enter Your Choice:[0-13]****|
----------------------------------------
1. 修改字符集
2. 关闭selinux
3. 关闭firewalld
4. 精简开机启动
5. 修改文件描述符
6. 安装常用工具及修改yum源
7. 优化系统内核
8. 加快ssh登录速度
9. 禁用ctrl+alt+del重启
10.设置时间同步
11.history优化
12.返回上级菜单
13.退出
EOF
 read -p "please enter your choice[1-13]:" num2
 
}

#1.修改字符集
localeset()
{
 echo "========================修改字符集========================="
 cat > /etc/locale.conf <<EOF
LANG="zh_CN.UTF-8"
#LANG="en_US.UTF-8"
SYSFONT="latarcyrheb-sun16"
EOF
 source /etc/locale.conf
 echo "#cat /etc/locale.conf"
 cat /etc/locale.conf
 action "完成修改字符集" /bin/true
 echo "==========================================================="
 sleep 2
}

#2.关闭selinux
selinuxset() 
{
 selinux_status=`grep "SELINUX=disabled" /etc/sysconfig/selinux | wc -l`
 echo "========================禁用SELINUX========================"
 if [ $selinux_status -eq 0 ];then
  sed  -i "s#SELINUX=enforcing#SELINUX=disabled#g" /etc/sysconfig/selinux
  setenforce 0
  echo '#grep SELINUX=disabled /etc/sysconfig/selinux'
  grep SELINUX=disabled /etc/sysconfig/selinux
  echo '#getenforce'
  getenforce
 else
  echo 'SELINUX已处于关闭状态'
  echo '#grep SELINUX=disabled /etc/sysconfig/selinux'
                grep SELINUX=disabled /etc/sysconfig/selinux
                echo '#getenforce'
                getenforce
 fi
  action "完成禁用SELINUX" /bin/true
 echo "==========================================================="
 sleep 2
}

#3.关闭firewalld
firewalldset()
{
 echo "=======================禁用firewalld========================"
 systemctl stop firewalld.service &> /dev/null
 echo '#firewall-cmd  --state'
 firewall-cmd  --state
 systemctl disable firewalld.service &> /dev/null
 echo '#systemctl list-unit-files | grep firewalld'
 systemctl list-unit-files | grep firewalld
 action "完成禁用firewalld，生产环境下建议启用！" /bin/true
 echo "==========================================================="
 sleep 5
}

#4.精简开机启动
chkset()
{
 echo "=======================精简开机启动========================"
 systemctl disable auditd.service
 systemctl disable postfix.service
 systemctl disable dbus-org.freedesktop.NetworkManager.service
 echo '#systemctl list-unit-files | grep -E "auditd|postfix|dbus-org\.freedesktop\.NetworkManager"'
 systemctl list-unit-files | grep -E "auditd|postfix|dbus-org\.freedesktop\.NetworkManager"
 action "完成精简开机启动" /bin/true
 echo "==========================================================="
 sleep 2
}

#5.修改文件描述符
limitset()
{
 echo "======================修改文件描述符======================="
 echo '* - nofile 65535'>/etc/security/limits.conf
 ulimit -SHn 65535
 echo "#cat /etc/security/limits.conf"
 cat /etc/security/limits.conf
 echo "#ulimit -Sn ; ulimit -Hn"
 ulimit -Sn ; ulimit -Hn
 action "完成修改文件描述符" /bin/true
 echo "==========================================================="
 sleep 2
}

#6.安装常用工具及修改yum源
yumset()
{
 echo "=================安装常用工具及修改yum源==================="
 yum install wget -y &> /dev/null
 if [ $? -eq 0 ];then
  cd /etc/yum.repos.d/
  \cp CentOS-Base.repo CentOS-Base.repo.$(date +%F)
  ping -c 1 mirrors.aliyun.com &> /dev/null
  if [ $? -eq 0 ];then
   wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo &> /dev/null
   yum clean all &> /dev/null
   yum makecache &> /dev/null
  else
   echo "无法连接网络"
       exit $?
    fi
 else
  echo "wget安装失败"
  exit $?
 fi
 yum -y install ntpdate lsof net-tools telnet vim lrzsz tree nmap nc sysstat &> /dev/null
 action "完成安装常用工具及修改yum源" /bin/true
 echo "==========================================================="
 sleep 2
}

#7. 优化系统内核
kernelset()
{
 echo "======================优化系统内核========================="
 chk_nf=`cat /etc/sysctl.conf | grep conntrack |wc -l`
 if [ $chk_nf -eq 0 ];then
  cat >>/etc/sysctl.conf<<EOF
net.ipv4.tcp_fin_timeout = 2
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_keepalive_time = 600
net.ipv4.ip_local_port_range = 4000 65000
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_max_tw_buckets = 36000
net.ipv4.route.gc_timeout = 100
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_synack_retries = 0
net.core.somaxconn = 16384
net.core.netdev_max_backlog = 16384
net.ipv4.tcp_max_orphans = 16384
net.netfilter.nf_conntrack_max = 25000000
net.netfilter.nf_conntrack_tcp_timeout_established = 180
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
EOF
 sysctl -p
 else
  echo "优化项已存在。"
 fi
 action "内核调优完成" /bin/true
 echo "==========================================================="
 sleep 2
}

#8.加快ssh登录速度
sshset()
{
 echo "======================加快ssh登录速度======================"
 sed -i 's#^GSSAPIAuthentication yes$#GSSAPIAuthentication no#g' /etc/ssh/sshd_config
 sed -i 's/#UseDNS yes/UseDNS no/g' /etc/ssh/sshd_config
 systemctl restart sshd.service
 echo "#grep GSSAPIAuthentication /etc/ssh/sshd_config"
 grep GSSAPIAuthentication /etc/ssh/sshd_config
 echo "#grep UseDNS /etc/ssh/sshd_config"
 grep UseDNS /etc/ssh/sshd_config
 action "完成加快ssh登录速度" /bin/true
 echo "==========================================================="
 sleep 2
}

#9. 禁用ctrl+alt+del重启
restartset()
{
 echo "===================禁用ctrl+alt+del重启===================="
 rm -rf /usr/lib/systemd/system/ctrl-alt-del.target
 action "完成禁用ctrl+alt+del重启" /bin/true
 echo "==========================================================="
 sleep 2
}

#10. 设置时间同步
ntpdateset()
{
 echo "=======================设置时间同步========================"
 yum -y install ntpdate &> /dev/null
 if [ $? -eq 0 ];then
  /usr/sbin/ntpdate time.windows.com
  echo "*/5 * * * * /usr/sbin/ntpdate ntp.aliyun.com &>/dev/null" >> /var/spool/cron/root
 else
  echo "ntpdate安装失败"
  exit $?
 fi
 action "完成设置时间同步" /bin/true
 echo "==========================================================="
 sleep 2
}

#11. history优化
historyset()
{
 echo "========================history优化========================"
 chk_his=`cat /etc/profile | grep HISTTIMEFORMAT |wc -l`
 if [ $chk_his -eq 0 ];then
  cat >> /etc/profile <<'EOF'
#设置history格式
export HISTTIMEFORMAT="[%Y-%m-%d %H:%M:%S] [`whoami`] [`who am i|awk '{print $NF}'|sed -r 's#[()]##g'`]: "
#记录shell执行的每一条命令
export PROMPT_COMMAND='\
if [ -z "$OLD_PWD" ];then
    export OLD_PWD=$PWD;
fi;
if [ ! -z "$LAST_CMD" ] && [ "$(history 1)" != "$LAST_CMD" ]; then
    logger -t `whoami`_shell_dir "[$OLD_PWD]$(history 1)";
fi;
export LAST_CMD="$(history 1)";
export OLD_PWD=$PWD;'
EOF
  source /etc/profile
 else
  echo "优化项已存在。"
 fi
 action "完成history优化" /bin/true
 echo "==========================================================="
 sleep 2
}

#控制函数
main()
{
 menu1
 case $num1 in
  1)
   localeset
   selinuxset
   firewalldset
   chkset
   limitset
   yumset
   kernelset
   sshset
   restartset
   ntpdateset
   historyset
   ;;
  2)
   menu2
   case $num2 in
                  1)
                    localeset
                    ;;
                  2)
                    selinuxset
                    ;;
                  3)
                    firewalldset
                    ;;
                  4)
                    chkset
                    ;;
                  5)
                    limitset
                    ;;
                  6)     
            yumset
                    ;;
                  7)
                    kernelset
                    ;;
                  8)
                    sshset
                    ;;
                  9)
                    restartset
                    ;;
                  10)
                    ntpdateset
                    ;;
    11)
      historyset
      ;;
    12)
      main
      ;;
    13)
      exit
      ;;
    *)
      echo 'Please select a number from [1-13].'
      ;;
   esac
   ;;
  3)
   exit
   ;;
  *)
   echo 'Err:Please select a number from [1-3].'
   sleep 3
   main
   ;;
 esac
}
main $*

将其保存为init.sh，然后赋予执行权限后执行即可。

chmod +x init.sh && ./init.sh

如果这样来回地复制粘贴很麻烦，也可以通过我的一键命令执行，同样能达到上面的效果：

bash -c "$(curl -L s.aaa.al/init.sh)"

最后，如果大家有想实现的功能，也可以在原有脚本的基础上进行修改实现。