#!/bin/bash
# 初始化Linux服务器脚本
# 功能：1. 时钟同步配置 2. Yum加速配置 3. 系统基础优化

# 检查是否为root用户
if [ $(id -u) != "0" ]; then
    echo "错误：请使用root用户执行此脚本"
    exit 1
fi

# 定义颜色变量
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

echo -e "${GREEN}开始初始化系统配置...${NC}"

# 1. 配置时钟同步
echo -e "${YELLOW}1. 配置时钟同步服务...${NC}"
# 安装chrony时间同步服务
yum install -y chrony

# 配置chrony使用国内时间服务器
cat > /etc/chrony.conf <<EOF
server ntp.aliyun.com iburst
server ntp1.aliyun.com iburst
server ntp.ntsc.ac.cn iburst
driftfile /var/lib/chrony/drift
makestep 1.0 3
rtcsync
allow 192.168/16
local stratum 10
keyfile /etc/chrony.keys
commandkey 1
generatecommandkey
noclientlog
logchange 0.5
logdir /var/log/chrony
EOF

# 启动并设置开机自启
systemctl enable chronyd --now
timedatectl set-timezone Asia/Shanghai
chronyc sources

echo -e "${GREEN}时钟同步配置完成${NC}"

# 2. 配置国内Yum镜像源
echo -e "${YELLOW}2. 配置阿里云Yum镜像源...${NC}"
# 备份原配置文件
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak

# 生成新的配置文件（适配CentOS 7/8）
cat > /etc/yum.repos.d/CentOS-Base.repo <<EOF
# CentOS-Base.repo
[base]
name=CentOS-\$releasever - Base - Aliyun
baseurl=http://mirrors.aliyun.com/centos/\$releasever/AppStream/\$basearch/os/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official

[appstream]
name=CentOS-\$releasever - AppStream - Aliyun
baseurl=http://mirrors.aliyun.com/centos/\$releasever/AppStream/\$basearch/os/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official

[extras]
name=CentOS-\$releasever - Extras - Aliyun
baseurl=http://mirrors.aliyun.com/centos/\$releasever/extras/\$basearch/os/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official

[centosplus]
name=CentOS-\$releasever - Plus - Aliyun
baseurl=http://mirrors.aliyun.com/centos/\$releasever/centosplus/\$basearch/os/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
EOF

# 生成缓存
yum clean all
yum makecache

echo -e "${GREEN}Yum镜像源配置完成${NC}"

# 3. 系统基础优化
echo -e "${YELLOW}3. 执行系统基础优化...${NC}"
# 关闭SELinux
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
setenforce 0

# 关闭防火墙（生产环境慎用）
systemctl stop firewalld
systemctl disable firewalld

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

# 优化内核参数
cat >> /etc/sysctl.conf <<EOF
net.ipv4.tcp_fin_timeout = 10
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_max_syn_backlog = 8192
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_rmem = 4096 87380 6291456
net.ipv4.tcp_wmem = 4096 65536 6291456
net.core.somaxconn = 65535
net.core.netdev_max_backlog = 65535
EOF

sysctl -p

echo -e "${GREEN}系统基础优化完成${NC}"

echo -e "${GREEN}所有初始化配置已完成！建议重启系统后使用${NC}"