系统初始化脚本

下面分享一个系统安装后的初始化脚本：

Centos6

#!/bin/bash
# Description: script to init configuration to new server.
#--------------------------------------------------------------|
#   @Program    : System_init.sh                               |  
#   @Version    : 1.1                                          |
#   @Company    : QWKG                                         |
#   @Dep.       : IDC                                          |
#   @Writer     : wangshibo   <wangshibo@veredholdings.com>    |                
#   @Date       : 2017-11-07                                   |
#   @Modify     : wangshibo                                    |
#--------------------------------------------------------------|

#临时dns设置，用于yum下载
echo "nameserver 8.8.8.8" /etc/resolv.conf
echo "nameserver 8.8.4.4" /etc/resolv.conf

#设置ntp时间服务
/usr/bin/yum install -y ntpdate
/usr/sbin/ntpdate 10.0.11.26
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.26 > /dev/null 2>&1" >>/var/spool/cron/root
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.27 > /dev/null 2>&1" >>/var/spool/cron/root
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.28 > /dev/null 2>&1" >>/var/spool/cron/root
chmod 600 /var/spool/cron/root

#关闭防火墙
iptables -F
iptables -X
chkconfig iptables off > /dev/null 2>&1
service iptables stop > /dev/null 2>&1
sed -i 's/SELINUX=enforcing/SELINUX=disabled/'  /etc/selinux/config 

#设置DNS
\cp -f /etc/resolv.conf /etc/resolv.conf.bak
> /etc/resolv.conf
echo "domain veredholdings.cn" >> /etc/resolv.conf
echo "search veredholdings.cn" >> /etc/resolv.conf
echo "nameserver 10.0.11.21" >> /etc/resolv.conf
echo "nameserver 10.0.11.22" >> /etc/resolv.conf
/usr/bin/chattr +ai /etc/resolv.conf

#更换为内网yum源
cd /etc/yum.repos.d/
/bin/mkdir /etc/yum.repos.d/bak
mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/bak
wget http://10.0.8.50/software/CentOS-Base.repo
wget http://10.0.8.50/software/epel.repo
/usr/bin/yum clean all
/usr/bin/yum makecache

#内核参数优化
/bin/cat << EOF > /etc/sysctl.conf
kernel.sysrq = 1
kernel.core_uses_pid = 1
fs.aio-max-nr = 1048576                
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.ip_forward = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.rp_filter = 2
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.all.arp_announce = 2
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.ip_local_port_range = 1024  65535
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_synack_retries = 2
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.rp_filter = 1
net.core.somaxconn = 65535
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 8192 87380 16777216
net.ipv4.tcp_wmem = 8192 65536 16777216
net.ipv4.tcp_max_syn_backlog = 16384
net.core.netdev_max_backlog = 10000
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_max_orphans = 131072
#fs.file-max = 65536  #os can config
vm.min_free_kbytes = 1048576
vm.swappiness = 10
vm.dirty_ratio = 10
vm.vfs_cache_pressure=150
vm.drop_caches = 1
kernel.panic = 60
EOF
/sbin/sysctl -p >/dev/null 2>&1;

#ssh登陆优化
cp /etc/ssh/sshd_config{,.bak}  
#sed -e 's/\#PermitRootLogin yes/PermitRootLogin no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
sed -e 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
sed -e 's/#UseDNS yes/UseDNS no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
/etc/init.d/sshd restart > /dev/null 2>&1

#修改文件描述符数量
sed -i 's_1024_65535_g' /etc/security/limits.d/90-nproc.conf
/bin/cp /etc/security/limits.conf /etc/security/limits.conf.bak
echo '* soft nofile 65535'>>/etc/security/limits.conf
echo '* hard nofile 65535'>>/etc/security/limits.conf
echo '* soft nproc 102400'>>/etc/security/limits.conf
echo '* hard nproc 102400'>>/etc/security/limits.conf

# 安装常用软件
/usr/bin/yum groupinstall "Development Tools"
/usr/bin/yum install -y gcc  glibc  gcc-c++ make  lrzsz  tree  wget curl lsof dstat vim wsmancli ipmitool mtr sysstat ethtool systemtap strace 

/bin/rm /root/idc_system_centos6_init.sh
# 最后重启服务器
reboot

Centos7

#!/bin/bash
# Description: script to init configuration to new server.
#--------------------------------------------------------------|
#   @Program    : System_init.sh                               |  
#   @Version    : 1.1                                          |
#   @Company    : QWKG                                         |
#   @Dep.       : IDC                                          |
#   @Writer     : wangshibo   <wangshibo@veredholdings.com>    |                
#   @Date       : 2017-11-07                                   |
#   @Modify     : wangshibo                                    |
#--------------------------------------------------------------|

#临时dns设置，用于yum下载
echo "nameserver 8.8.8.8" /etc/resolv.conf
echo "nameserver 8.8.4.4" /etc/resolv.conf

#设置ntp时间服务
/usr/bin/yum install -y ntpdate
/usr/sbin/ntpdate 10.0.11.26
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.26 > /dev/null 2>&1" >>/var/spool/cron/root
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.27 > /dev/null 2>&1" >>/var/spool/cron/root
echo "*/5 * * * * /usr/sbin/ntpdate 10.0.11.28 > /dev/null 2>&1" >>/var/spool/cron/root
chmod 600 /var/spool/cron/root

#关闭防火墙
iptables -F
iptables -X
systemctl stop firewalld.service
systemctl disable firewalld.service 
sed -i 's/SELINUX=enforcing/SELINUX=disabled/'  /etc/selinux/config 

#设置DNS
\cp -f /etc/resolv.conf /etc/resolv.conf.bak
> /etc/resolv.conf
echo "domain veredholdings.cn" >> /etc/resolv.conf
echo "search veredholdings.cn" >> /etc/resolv.conf
echo "nameserver 10.0.11.21" >> /etc/resolv.conf
echo "nameserver 10.0.11.22" >> /etc/resolv.conf
/usr/bin/chattr +ai /etc/resolv.conf

#更换为内网yum源
cd /etc/yum.repos.d/
/bin/mkdir /etc/yum.repos.d/bak
mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/bak
wget http://10.0.8.50/software/CentOS-Base.repo
wget http://10.0.8.50/software/epel.repo
/usr/bin/yum clean all
/usr/bin/yum makecache

#内核参数优化
/bin/cat << EOF > /etc/sysctl.conf
kernel.sysrq = 1
kernel.core_uses_pid = 1
fs.aio-max-nr = 1048576                
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.ip_forward = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.rp_filter = 2
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.all.arp_announce = 2
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.ip_local_port_range = 1024  65535
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_synack_retries = 2
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.rp_filter = 1
net.core.somaxconn = 65535
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 8192 87380 16777216
net.ipv4.tcp_wmem = 8192 65536 16777216
net.ipv4.tcp_max_syn_backlog = 16384
net.core.netdev_max_backlog = 10000
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_max_orphans = 131072
#fs.file-max = 65536  #os can config
vm.min_free_kbytes = 1048576
vm.swappiness = 10
vm.dirty_ratio = 10
vm.vfs_cache_pressure=150
vm.drop_caches = 1
kernel.panic = 60
EOF
/sbin/sysctl -p >/dev/null 2>&1;

#ssh登陆优化
cp /etc/ssh/sshd_config{,.bak}  
#sed -e 's/\#PermitRootLogin yes/PermitRootLogin no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
sed -e 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
sed -e 's/#UseDNS yes/UseDNS no/' -i /etc/ssh/sshd_config > /dev/null 2>&1
systemctl restart sshd.service

#修改文件描述符数量
sed -i 's#4096#65535#g' /etc/security/limits.d/20-nproc.conf
/bin/cp /etc/security/limits.conf /etc/security/limits.conf.bak
echo '* soft nofile 65535'>>/etc/security/limits.conf
echo '* hard nofile 65535'>>/etc/security/limits.conf
echo '* soft nproc 102400'>>/etc/security/limits.conf
echo '* hard nproc 102400'>>/etc/security/limits.conf

# 安装常用软件
/usr/bin/yum groupinstall "Development Tools"
/usr/bin/yum install -y gcc  glibc  gcc-c++ make  lrzsz  tree  wget curl lsof dstat vim wsmancli ipmitool mtr sysstat ethtool systemtap strace 

/bin/rm /root/idc_system_centos7_init.sh
# 最后重启服务器
reboot

用这个：

#禁用包过滤功能
net.ipv4.ip_forward = 0 
#启用源路由核查功能
net.ipv4.conf.default.rp_filter = 1 
#禁用所有IP源路由
net.ipv4.conf.default.accept_source_route = 0 
#使用sysrq组合键是了解系统目前运行情况，为安全起见设为0关闭
kernel.sysrq = 0 
#控制core文件的文件名是否添加pid作为扩展
kernel.core_uses_pid = 1 
#开启SYN Cookies，当出现SYN等待队列溢出时，启用cookies来处理
net.ipv4.tcp_syncookies = 1 
#每个消息队列的大小（单位：字节）限制
kernel.msgmnb = 65536 
#整个系统最大消息队列数量限制
kernel.msgmax = 65536 
#单个共享内存段的大小（单位：字节）限制，计算公式64G*1024*1024*1024(字节)
kernel.shmmax = 68719476736 
#所有内存大小（单位：页，1页 = 4Kb），计算公式16G*1024*1024*1024/4KB(页)
kernel.shmall = 4294967296 
#timewait的数量，默认是180000
net.ipv4.tcp_max_tw_buckets = 6000 
#开启有选择的应答
net.ipv4.tcp_sack = 1 
#支持更大的TCP窗口. 如果TCP窗口最大超过65535(64K), 必须设置该数值为1
net.ipv4.tcp_window_scaling = 1 
#TCP读buffer
net.ipv4.tcp_rmem = 4096 131072 1048576
#TCP写buffer
net.ipv4.tcp_wmem = 4096 131072 1048576  
#为TCP socket预留用于发送缓冲的内存默认值（单位：字节）
net.core.wmem_default = 8388608
#为TCP socket预留用于发送缓冲的内存最大值（单位：字节）
net.core.wmem_max = 16777216 
#为TCP socket预留用于接收缓冲的内存默认值（单位：字节） 
net.core.rmem_default = 8388608
#为TCP socket预留用于接收缓冲的内存最大值（单位：字节）
net.core.rmem_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 
#web应用中listen函数的backlog默认会给我们内核参数的net.core.somaxconn限制到128，而nginx定义的NGX_LISTEN_BACKLOG默认为511，所以有必要调整这个值
net.core.somaxconn = 262144 
#系统中最多有多少个TCP套接字不被关联到任何一个用户文件句柄上。这个限制仅仅是为了防止简单的DoS攻击，不能过分依靠它或者人为地减小这个值，更应该增加这个值(如果增加了内存之后)
net.ipv4.tcp_max_orphans = 3276800 
#记录的那些尚未收到客户端确认信息的连接请求的最大值。对于有128M内存的系统而言，缺省值是1024，小内存的系统则是128
net.ipv4.tcp_max_syn_backlog = 262144 
#时间戳可以避免序列号的卷绕。一个1Gbps的链路肯定会遇到以前用过的序列号。时间戳能够让内核接受这种“异常”的数据包。这里需要将其关掉
net.ipv4.tcp_timestamps = 0 
#为了打开对端的连接，内核需要发送一个SYN并附带一个回应前面一个SYN的ACK。也就是所谓三次握手中的第二次握手。这个设置决定了内核放弃连接之前发送SYN+ACK包的数量
net.ipv4.tcp_synack_retries = 1 
#在内核放弃建立连接之前发送SYN包的数量
net.ipv4.tcp_syn_retries = 1 
#开启TCP连接中time_wait sockets的快速回收
net.ipv4.tcp_tw_recycle = 1 
#开启TCP连接复用功能，允许将time_wait sockets重新用于新的TCP连接（主要针对time_wait连接）
net.ipv4.tcp_tw_reuse = 1 
#1st低于此值,TCP没有内存压力,2nd进入内存压力阶段,3rdTCP拒绝分配socket(单位：内存页)
net.ipv4.tcp_mem = 94500000 915000000 927000000  
#如果套接字由本端要求关闭，这个参数决定了它保持在FIN-WAIT-2状态的时间。对端可以出错并永远不关闭连接，甚至意外当机。缺省值是60 秒。2.2 内核的通常值是180秒，你可以按这个设置，但要记住的是，即使你的机器是一个轻载的WEB服务器，也有因为大量的死套接字而内存溢出的风险，FIN- WAIT-2的危险性比FIN-WAIT-1要小，因为它最多只能吃掉1.5K内存，但是它们的生存期长些。
net.ipv4.tcp_fin_timeout = 15 
#表示当keepalive起用的时候，TCP发送keepalive消息的频度（单位：秒）
net.ipv4.tcp_keepalive_time = 30 
#对外连接端口范围
net.ipv4.ip_local_port_range = 2048 65000
#表示文件句柄的最大数量
fs.file-max = 102400

# 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

# 开启SYN洪水攻击保护
net.ipv4.tcp_syncookies = 1

# 开启并记录欺骗，源路由和重定向包
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 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

# 开启反向路径过滤
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1

# 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

# 不充当路由器
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0

# 开启execshild
kernel.exec-shield = 1
kernel.randomize_va_space = 1

# IPv6设置
net.ipv6.conf.default.router_solicitations = 0
net.ipv6.conf.default.accept_ra_rtr_pref = 0
net.ipv6.conf.default.accept_ra_pinfo = 0
net.ipv6.conf.default.accept_ra_defrtr = 0
net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.default.dad_transmits = 0
net.ipv6.conf.default.max_addresses = 1

# 优化LB使用的端口

# 增加系统文件描述符限制
fs.file-max = 65535

# 允许更多的PIDs (减少滚动翻转问题); may break some programs 32768
kernel.pid_max = 65536

# 增加系统IP端口限制
net.ipv4.ip_local_port_range = 2000 65000

# 增加TCP最大缓冲区大小
net.ipv4.tcp_rmem = 4096 87380 8388608
net.ipv4.tcp_wmem = 4096 87380 8388608

# 增加Linux自动调整TCP缓冲区限制
# 最小，默认和最大可使用的字节数
# 最大值不低于4MB，如果你使用非常高的BDP路径可以设置得更高

# Tcp窗口等
net.core.rmem_max = 8388608
net.core.wmem_max = 8388608
net.core.netdev_max_backlog = 5000
net.ipv4.tcp_window_scaling = 1