[root@test2 yum.repos.d]# cat centos7.sh

#!/bin/bash

#author junxi by 

#this script is only for CentOS 7.x

#check the OS

platform=`uname -i`

if [ $platform != "x86_64" ];then 

echo "this script is only for 64bit Operating System !"

exit 1

fi

echo "the platform is ok"

cat << EOF

+---------------------------------------+

|   your system is CentOS 7 x86_64      |

|      start optimizing.......          |

+---------------------------------------+

EOF

 

#添加公网DNS地址

cat >> /etc/resolv.conf << EOF

nameserver 223.6.6.6

EOF

#Yum源更换为国内阿里源

yum install wget -y

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

#添加阿里的epel源

#add the epel

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

#yum重新建立缓存

yum clean all

yum makecache

#同步时间

yum -y install ntp

/usr/sbin/ntpdate ntp1.aliyun.com

echo "* 4 * * * /usr/sbin/ntpdate ntp1.aliyun.com > /dev/null 2>&1" >> /var/spool/cron/root

systemctl restart crond.service

#设置主机名

hostnamectl set-hostname qiuyuetao

#设置字符集

#设置最大打开文件描述符数

echo "ulimit -SHn 102400" >> /etc/rc.local

cat >> /etc/security/limits.conf << EOF

*           soft   nofile       655350

*           hard   nofile       655350

EOF

#禁用selinux

sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

setenforce 0

#关闭防火墙

systemctl disable firewalld.service 

systemctl stop firewalld.service 

#set ssh

sed -i 's/^GSSAPIAuthentication yes$/GSSAPIAuthentication no/' /etc/ssh/sshd_config

sed -i 's/#UseDNS yes/UseDNS no/' /etc/ssh/sshd_config

systemctl  restart sshd.service

#内核参数优化

cat >> /etc/sysctl.conf << EOF

#CTCDN系统优化参数

#关闭ipv6

net.ipv6.conf.all.disable_ipv6 = 1

net.ipv6.conf.default.disable_ipv6 = 1

#决定检查过期多久邻居条目

net.ipv4.neigh.default.gc_stale_time=120

#使用arp_announce / arp_ignore解决ARP映射问题

net.ipv4.conf.default.arp_announce = 2

net.ipv4.conf.all.arp_announce=2

net.ipv4.conf.lo.arp_announce=2

# 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 = 0

#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 = 1800

net.ipv4.tcp_keepalive_probes = 3

net.ipv4.tcp_keepalive_intvl = 15

#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

EOF

/sbin/sysctl -p

#vim定义退格键可删除最后一个字符类型

echo 'alias vi=vim' >> /etc/profile

echo 'stty erase ^H' >> /etc/profile

echo 'curl ip.6655.com/ip.aspx&&echo' >> /etc/profile

cat >> /root/.vimrc << EOF

set tabstop=4

set shiftwidth=4

set expandtab

syntax on

"set number

EOF

#update soft

yum -y update 

cat << EOF

+------------------------------------------------+

|                优 化 已 完 成                    |

|             5s 后 重启 这台服务器 !               |

+------------------------------------------------+

EOF

sleep 5

reboot  ##重启加载内核修改

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm

yum --enablerepo=elrepo-kernel install kernel-ml -y&&

sed -i s/saved/0/g /etc/default/grub&&

grub2-mkconfig -o /boot/grub2/grub.cfg && reboot

#不重启不生效！