01 Linux系统配置初始化

#/bin/bash
export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

# 更改主机名
# hostnamectl set-hostname <hostname>

# 隐藏服务器版本
> /etc/issue

# 修改字符集
localectl set-locale LANG=en_US.UTF-8

# 解决ssh连接速度慢的问题
sed -i '/GSSAPIAuthentication/{s/yes/no/}' /etc/ssh/sshd_config
sed -i 's/#UseDNS yes/UseDNS no/' /etc/ssh/sshd_config
# sed -i '134i GSSAPIAuthentication no
UseDNS no' /etc/ssh/sshd_config

# 更新yum源
if egrep "7.[0-9]" /etc/redhat-release &>/dev/null; then
    wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
    wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
elif egrep "6.[0-9]" /etc/redhat-release &>/dev/null; then
    wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-6.repo
    wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
fi
yum clean all

# 设置时区并同步时间
ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
if ! crontab -l | grep "ntpdate" &>/dev/null; then
    (echo "*/5 * * * * /usr/sbin/ntpdate ntp.aliyun.com >/dev/null 2>&1"; crontab -l) | crontab
fi

# 禁用selinux
sed -i '/SELINUX/{s/enforcing/disabled/}' /etc/selinux/config

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

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

# 历史命令显示操作时间；命令行历史数；忽略所有以空格开头的命令。
if ! grep "HISTTIMEFORMAT" /etc/profile &>/dev/null; then
    echo 'export HISTTIMEFORMAT="%F %T `whoami` "' >> /etc/profile
    echo "export HISTSIZE=50" >>/etc/profile
    echo "export HISTFILESIZE=50" >> /etc/profile
    echo "export HISTCONTROL=ignorespace" >>/etc/profile
fi

# SSH超时时间，改变umask
if ! grep "TMOUT=3600" /etc/profile &>/dev/null; then
    echo "export TMOUT=3600" >> /etc/profile
    echo "umask 022" >> /etc/profile
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
if ! grep "* soft nofile 65535" /etc/security/limits.conf &>/dev/null; then
cat >> /etc/security/limits.conf << EOF
    * soft nofile 65535
    * hard nofile 65535
EOF
fi

# 系统内核优化
if ! grep "net.ipv4" /etc/sysctl.conf &>/dev/null; then
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_tw_reuse = 1
net.ipv4.ip_local_port_range = 1024 65000
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
fi

# 减少SWAP使用
if ! grep "vm.swappiness" /etc/sysctl.conf &>/dev/null; then
cat >> /etc/sysctl.conf << EOF
vm.swappiness = 0
EOF
fi
# echo "0" > /proc/sys/vm/swappiness
# 临时生效

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

# 重启服务器
reboot