CentOS7安装完后常用优化设置

• Yum源更换为国内阿里源

yum install wget telnet -y
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

• 添加阿里的epel源

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
# rpm -ivh http://dl.Fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-8.noarch.rpm

• yum重新建立缓存

yum clean all
yum makecache

• 同步时间

yum -y install ntp
/usr/sbin/ntpdate cn.pool.ntp.org
echo "* 4 * * * /usr/sbin/ntpdate cn.pool.ntp.org > /dev/null 2>&1" >> /var/spool/cron/root
systemctl  restart crond.service

• 安装vim

yum -y install vim

• 设置最大打开文件描述符数

echo "ulimit -SHn 102400" >> /etc/rc.local
vim /etc/security/limits.conf
*           soft   nofile       655350
*           hard   nofile       655350

• 禁用selinux

sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
setenforce 0

• 关闭防火墙

systemctl disable firewalld.service 
systemctl stop firewalld.service 

• 配置 ssh

sed -i 's/^GSSAPIAuthentication yes$/GSSAPIAuthentication no/' /etc/ssh/sshd_config
sed -i 's/#UseDNS yes/UseDNS no/' /etc/ssh/sshd_config
systemctl  restart sshd.service

• 内核参数优化

cat >> /etc/sysctl.conf << EOF
vm.overcommit_memory = 1
net.ipv4.ip_local_port_range = 1024 65536
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_abort_on_overflow = 0
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.ipv4.netfilter.ip_conntrack_max = 2097152
net.nf_conntrack_max = 655360
net.netfilter.nf_conntrack_tcp_timeout_established = 1200
EOF
/sbin/sysctl -p

• vim定义退格键可删除最后一个字符类型

echo 'alias vi=vim' >> /etc/profile
echo 'stty erase ^H' >> /etc/profile
cat >> /root/.vimrc << EOF
set tabstop=4
set shiftwidth=4
set expandtab
syntax on
"set number
EOF

• 更新系统 update

yum -y update