系统初始化脚本

# [https://docs.opendevops.cn/](https://docs.opendevops.cn/)
#usage() {
#    echo "请按如下格式执行"
#    echo "USAGE: bash $0 函数名1#函数名2"
#    echo "USAGE: bash $0 epel#ulimits#ssh"
#    exit 1
#}
#

function epel(){
	yum install epel-release -y >/dev/null 2>&1
	sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/epel.repo
	sed -i 's/#baseurl/baseurl/g' /etc/yum.repos.d/epel.repo
	sed -i '6s/enabled=0/enabled=1/g' /etc/yum.repos.d/epel.repo
	sed -i '7s/gpgcheck=1/gpgcheck=0/g' /etc/yum.repos.d/epel.repo
	yum clean all >/dev/null 2>&1
	#阿里云机器用aliyun epel
	#echo "[EPEL 配置] ==> OK"
}

function ulimits(){
cat > /etc/security/limits.conf < /etc/security/limits.d/20-nproc.conf 

ulimit -n 65536
ulimit -u 65536


#echo "[ulimits 配置] ==> OK"


}


# 系统默认没有 /etc/init.d/sshd 需要使用 systemctl restart  sshd
function ssh(){
	[ -f /etc/ssh/sshd_config ]  && sed -ir '13 iUseDNS no\nGSSAPIAuthentication no' /etc/ssh/sshd_config && systemctl restart  sshd >/dev/null 2>&1
#echo "[SSH 优化] ==> OK"
}

# 修改内核参数，增加缓存区，减少等待时间
# 可以接收更大的包，增加对轻量ddos抗性
function kernel(){
cat > /etc/sysctl.conf </dev/null 2>&1
#echo "[内核 优化] ==> OK"
}

# 增加操作系统记录数量
function history(){
	if ! grep "HISTTIMEFORMAT" /etc/profile >/dev/null 2>&1
	then echo '
	UserIP=$(who -u am i | cut -d"("  -f 2 | sed -e "s/[()]//g")
	export HISTTIMEFORMAT="[%F %T] [`whoami`] [${UserIP}] " ' >> /etc/profile;
	fi
	sed -i "s/HISTSIZE=1000/HISTSIZE=999999999/" /etc/profile
#echo "[history 优化] ==> OK"
}

# 这个稍后我再试一试，我是倾向不要关闭selinux，而是使用系统权限完善来控制软件运行。
# 稍后测试一下看看
function security(){
	> /etc/issue
	sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
	sed -i 's/SELINUX=permissive/SELINUX=disabled/g' /etc/selinux/config
	setenforce 0 >/dev/null 2>&1
	#systemctl stop firewalld.service
	#systemctl disable firewalld.service
	yum install -y openssl openssh bash >/dev/null 2>&1
	#echo "[安全配置] ==> OK"
}

function other(){
	yum groupinstall Development tools -y >/dev/null 2>&1
	yum install -y vim wget lrzsz telnet traceroute iotop tree >/dev/null 2>&1
	yum install -y ncftp axel git zlib-devel openssl-devel unzip xz libxslt-devel libxml2-devel libcurl-devel >/dev/null 2>&1
	#echo "[安装常用工具] ==> OK"
	echo "export HOME=/root" >> /etc/profile
	source /etc/profile
	useradd -M -s /sbin/nologin nginx >/dev/null 2>&1
	mkdir -p /root/ops_scripts /data1/www
	mkdir -p /opt/codo/
}

export -f epel
export -f ulimits
export -f ssh
export -f kernel
export -f history
export -f security
export -f other

##格式必须是: bash script 函数名1#函数2
## 例如: bash system_init_v1.sh epel#ulimits#ssh
#echo $1 | awk -F "#" '{for(i=1;i<=NF;++i) system($i)}'
epel
ulimits
ssh
kernel
history
security
other
#echo '[Success]System Init OK'