CentOS 6.X system initialization script

   Copyright statement: This article is an original article by Shaon Puppet. Please indicate the original address for reprinting. Thank you very much. https://blog.csdn.net/wh211212/article/details/52817795

#! /bin/bash 

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- - Info

Initialization CentOS 6.x script

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Changelog

20160601 shaonbean initial creation

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Auther: [email protected]

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Check if user is root

if [ $(id -u) != "0" ]; then
echo "Error: You must be root to run this script, please use root to initialization OS"
exit 1
fi

echo "+------------------------------------------------------------------------+"
echo "| To initialization the system for security and performance |"
echo "+------------------------------------------------------------------------+"

check host && network

check_hosts()
{
hostname=hostname
if grep -Eqi '^127.0.0.1[[:space:]]*localhost' /etc/hosts; then
echo "Hosts: ok."
else
echo "127.0.0.1 localhost.localdomain $hostname" >> /etc/hosts
fi
ping -c1 www.aniu.tv
if [ $? -eq 0 ] ; then
echo "DNS...ok"
echo "nameserver 8.8.8.8" >> /etc/resolv.conf
else
echo "DNS...fail"
echo -e "nameserver 8.8.8.8\nnameserver 114.114.114.114" > /etc/resolv.conf
fi
}

Set time zone synchronization

set_timezone()
{
echo "Setting timezone..."
rm -rf /etc/localtime
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

install ntp

echo "[+] Installing ntp..."
yum install ntpdate -y
/usr/sbin/ntpdate pool.ntp.org
echo '*/5 * * * * /usr/sbin/ntpdate pool.ntp.org > /dev/null 2>&1' > /var/spool/cron/root;chmod 600 /var/spool/cron/root
/sbin/service crond restart
}

update os

update(){
yum -y update

change yum source

cd /etc/yum.repos.d/

mkdir bak

mv ./*.repo bak

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo

yum clean all && yum makecache

yum -y install wget vim unzip openssl-devel gcc gcc-c++ sysstat iotop openssh-clients telnet lsof
echo "yum update && yum install common command ......... succeed."
}

selinux()
{
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
setenforce 0
echo "disbale selinux ..................succeed."
}

xen_hwcap_setting()

#{

if [ -s /etc/ld.so.conf.d/libc6-xen.conf ]; then

sed -i 's/hwcap 1 nosegneg/hwcap 0 nosegneg/g' /etc/ld.so.conf.d/libc6-xen.conf

fi

#}

Modify file open number,define 1024

/etc/security/limits.conf

limits_config()
{
cat >> /etc/security/limits.conf <<EOF

• soft nproc 65535
• hard nproc 65535
• soft nofile 8192
• hard nofile 8192
  EOF

ulimit -n 8192

echo "ulimit -SHn 65535" >> /etc/rc.local
}

ulimit -n 8192

Shut off system service

stop_server()
{
echo "stop not nessccery services!"
for server in chkconfig --list |grep 3:on|awk '{ print $1}'
do
chkconfig --level 3 $server off
done

for server in crond network rsyslog sshd lvm2-monitor sysstat netfs blk-availability udev-post
do
chkconfig --level 3 $server on
done
}

define sshd

sshd_config(){

sed -i '/^#Port/s/#Port 22/Port 54077/g' /etc/ssh/sshd_config

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

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

sed -i 's/#PermitEmptyPasswords no/PermitEmptyPasswords no/g' /etc/ssh/sshd_config
/etc/init.d/sshd restart
echo "set sshd && restat sshd succedd!"
}

iptables

iptables(){

disable iptables

/etc/init.d/iptables stop
chkconfig --level 3 iptables off

disable ipv6

echo "alias net-pf-10 off" >> /etc/modprobe.d/modprobe.conf
echo "alias ipv6 off" >> /etc/modprobe.d/modprobe.conf
echo "NETWORKING_IPV6=no" >> /etc/sysconfig/network
chkconfig --level 3 ip6tables off
/etc/init.d/ip6tables stop
echo "iptables is stop && ipv6 is disabled!"
}

other(){

initdefault

sed -i 's/^id:.*$/id:3:initdefault:/' /etc/inittab
/sbin/init q

PS1

echo 'PS1="[\e[37;40m][[\e[32;40m]\u[\e[37;40m]@\h [\e[35;40m]\W[\e[0m]]\$ [\e[33;40m]"' >> /etc/profile

echo "TMOUT=7200" >> /etc/profile

Record command

sed -i 's/^HISTSIZE=.*$/HISTSIZE=1000/' /etc/profile

echo "export PROMPT_COMMAND='{ msg=$(history 1 | { read x y; echo $y; });user=$(whoami); echo $(date "+%Y-%m-%d %H:%M:%S"):$user:`pwd`/:$msg ---- $(who am i); } >> /tmp/`hostname`.`whoami`.history-timestamp'" >> /root/.bash_profile

wrong password five times locked 180s

sed -i '4a auth required pam_tally2.so deny=5 unlock_time=180' /etc/pam.d/system-auth

forbiden ctl-alt-delete

sed -i 's/exec /sbin/shutdown -r now "Control-Alt-Delete pressed"/#exec /sbin/shutdown -r now "Control-Alt-Delete pressed"/g' /etc/init/control-alt-delete.conf

source /etc/profile
}

delete_user()
{

delete no use user

echo "delete not use user"
echo ""
for user in adm lp sync shutdown halt uucp operator gopher
do userdel $user ; done
}

sysctl_add(){
cat >> /etc/sysctl.conf << EOF

appends

net.ipv4.tcp_synack_retries = 0
net.ipv4.tcp_max_syn_backlog = 20480
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 10
fs.file-max = 819200
net.core.somaxconn = 65536
net.core.rmem_max = 1024123000
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 165536
net.ipv4.ip_local_port_range = 10000 65535
EOF

set kernel parameters work

sysctl -p
}

main function

main(){
check_hosts
set_timezone
selinux
update
limits_config
stop_server
sshd_config
iptables
other
delete_user
sysctl_add
}

execute main functions

main

echo "+------------------------------------------------------------------------+"
echo "| To initialization system all completed !!! |"
echo "+------------------------------------------------------------------------+"