零、局域网机器应用

• 设置centOS源

cd /etc/yum.repos.d/
rename .repo .repo.bak ./*

cat << EOF > /etc/yum.repos.d/lan.repo
[centos7-lan]
name=CentOS-$releasever - lan
baseurl=http://192.168.20.162/centos7-local-repo/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF

yum clean all
yum repolist

• 安装常用软件，设置完本地源后使用

yum -y install lrzsz gcc+ gcc-c++ wget net-tools pcre-develyum openssl openssl-devel curl vim

• 设置ntp本地服务, 如需查看本地时间配置，用 timedatectl

yum -y remove chrony
yum install -y ntp ntpdate
timedatectl set-timezone Asia/Shanghai
timedatectl set-local-rtc 1
chkconfig --level 345 ntpd on

sed -i 's/^server.*iburst$/#&/' /etc/ntp.conf
echo "server 192.168.20.162 prefer" >> /etc/ntp.conf
systemctl enable ntpd 
systemctl restart ntpd 
ntpd -q

一、centos源

1.1、虚拟机挂载iso拷贝本地

虚拟机挂载iso，拷贝至本地,注：如只有iso文件也可以直接挂载为目录

mkdir -p /soft/centos7iso
mount /dev/cdrom /mnt
cp -r /mnt/* /soft/centos7iso/
umount /mnt

1.2、制作本地仓

依赖1.1

• 备份repo文件、创建本地目录型repo

cd /etc/yum.repos.d/
rename .repo .repo.bak ./*

cat << EOF > /etc/yum.repos.d/local.repo
[centos7-local]
name=CentOS-$releasever - local 
baseurl=file:///soft/centos7iso/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF

yum clean all
yum repolist

1.3、设置局域网源

依赖1.1

• 配置http服务（关闭ipv6、安装http、设置网络目录、检查80口状态)

sysctl net.ipv6.conf.all.disable_ipv6=1  

yum install -y lrzsz httpd yum-utils createrepo


mkdir -p /var/www/html/
cd /var/www/html/        
ln -s /soft/centos7iso/ centos7-local-repo
chcon -R -t httpd_sys_content_t /soft/centos7iso/

systemctl enable httpd
systemctl restart httpd
netstat -lntp 

• web访问测试

curl 'http://192.168.20.161/centos7-local-repo/'

• 创建局域网型repo

cat << EOF > /etc/yum.repos.d/lan.repo
[centos7-lan]
name=CentOS-$releasever - lan
baseurl=http://192.168.20.161/centos7-local-repo/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF

yum clean all
yum repolist

二、时间服务器

• 卸载、安装软件、修改时区、硬件时钟与软件一致（0为UTC）、并与阿里云ntp同步

yum -y remove chrony
yum install -y ntp ntpdate
timedatectl set-timezone Asia/Shanghai
timedatectl set-local-rtc 1
chkconfig --level 345 ntpd on


#主机本地时间（可选，如果偏差很大）
date -s "2021-2-22 14:40:45"

• 修改NTP,添加restrict访问网段、fudge晶振

vi /etc/ntp.conf
#----------------------------------------------------------
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org iburst
server 2.centos.pool.ntp.org iburst
server 3.centos.pool.ntp.org iburst

restrict 192.168.20.0 mask 255.255.255.0 nomodify notrap
restrict 127.0.0.1

#server 127.127.1.0 #local clock
fudge 127.127.1.0 stratum 10
#----------------------------------------------------------

#1号主机重启，激活配置
systemctl restart ntpd
ntpq -p

###所有主机进行时间同步，注意回显信息！！！
for i in {2..3}; do ssh hdp0$i ' systemctl stop ntpd'  ;done
for i in {2..3}; do ssh hdp0$i ' ntpdate hdp01'  ;done

#检查时间配置
for i in {1..3}; do ssh hdp0$i 'systemctl enable ntpd '  ;done
for i in {1..3}; do ssh hdp0$i 'systemctl start ntpd '  ;done
for i in {1..3}; do ssh hdp0$i ' ntpq -p'  ;done

三、dns？

操作系统优化

• 放开文件句柄数、设置swap、关闭透明大页面**

#统一调大为32768
echo "* soft nofile 100000" >> /etc/security/limits.conf
echo "* hard nofile 100000" >> /etc/security/limits.conf
echo "* soft noproc 65535" >> /etc/security/limits.conf
echo "* hard noproc 65535" >> /etc/security/limits.conf

reboot



#默认30，改为1，尽量用完物理内存

sysctl -q vm.swappiness
echo "vm.swappiness = 1" >> /etc/sysctl.conf
sysctl vm.swappiness=1






############################################################
#关闭透明大页面，如下脚本追加到vi /etc/rc.d/rc.local

if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
  echo never > /sys/kernel/mm/transparent_hugepage/enabled
fi
if test -f /sys/kernel/mm/transparent_hugepage/defrag; then
  echo never > /sys/kernel/mm/transparent_hugepage/defrag
fi

echo never > /sys/kernel/mm/transparent_hugepage/defrag
echo never > /sys/kernel/mm/transparent_hugepage/enabled