Linux系统初始化shell脚本

#/bin/sh
set -u
#用国内yum源
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
cd /etc/yum.repos.d/
curl -O http://mirrors.aliyun.com/repo/Centos-7.repo
yum clean all
yum makecache


# 设置时区并同步时间
yum -y install utp ntpdate && ntpdate cn.pool.ntp.org && hwclock --systohc && timedatectl set-timezone Asia/Shanghai

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

# 关闭防火墙
if egrep "7.[0-9]" /etc/redhat-release &>/dev/null; then
    systemctl stop firewalld
    systemctl disable firewalld
elif egrep "6.[0-9]" /etc/redhat-release &>/dev/null; then
    service iptables stop
    chkconfig iptables off
fi


# 禁止root远程登录
sed -i 's/#PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config

# 禁止定时任务向发送邮件
sed -i 's/^MAILTO=root/MAILTO=""/' /etc/crontab 

# 设置最大打开文件数
cat >> /etc/security/limits.conf << EOF
* soft nofile 65535
* hard nofile 65535
EOF

# 系统内核优化
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_fin_timeout = 20  
EOF

# 减少SWAP使用
echo "0" > /proc/sys/vm/swappiness

# 安装系统性能分析工具及其他
yum install gcc make autoconf vim sysstat net-tools iostat iftop iotp lrzsz  bash-completion rsync -y