centos7.X 系统初始化>>优化

1 修改网卡为eth0

cd /etc/sysconfig/network-scripts/

vim ifcfg-eno16777729
TYPE=Ethernet
BOOTPROTO=static
IPADDR=192.168.1.201
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
NAME=eth0
UUID=efd17b9a-a5ab-4c94-be62-d2c32eb48a7e
DEVICE=eth0
ONBOOT=yes
DNS1=202.106.0.20
mv ifcfg-eno16777729 ifcfg-eth0
vi /etc/sysconfig/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed ‘s, release .*$,,g‘ /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0 rhgb quiet" #添加 net.ifnames=0 biosdevname=0
GRUB_DISABLE_RECOVERY="true"

grub2-mkconfig -o /boot/grub2/grub.cfg #生成启动菜单
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-327.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-327.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-e8675ae79abd41309dac42388f8d9116
Found initrd image: /boot/initramfs-0-rescue-e8675ae79abd41309dac42388f8d9116.img
reboot
ip addr 或者
yum install net-tools #默认centos7不支持ifconfig 需要装net-tools包
ifconfig eth0 #在次查看网卡信息

2 更新系统

yum update -y

3 给/etc/rc.local添加执行权限

ll /etc/rc.locallrwxrwxrwx. 1 root root 13 Feb 6 07:28 /etc/rc.local -> rc.d/rc.local

ll /etc/rc.d/rc.local
-rw-r--r--. 1 root root 473 May 12 2016 /etc/rc.d/rc.local
chmod +x /etc/rc.d/rc.local

4 添加用户

hequan
useradd hequan
echo 123456 | passwd --stdin hequan
Changing password for user hequan.
passwd: all authentication tokens updated successfully.

usermod -G wheel hequan

sed -i ‘6s/^#//g‘ /etc/pam.d/su

grep wheel /etc/pam.d/su #只有WHEEL组的可以su
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth sufficient pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
auth required pam_wheel.so use_uid

扩展:为用户hequan添加sudo，除关机外的其他所有操作：

visudoCmnd_Alias SHUTDOWN = /sbin/halt, /sbin/shutdown, /sbin/poweroff, /sbin/reboot, /sbin/init
hequan ALL=(ALL) ALL,!SHUTDOWN
%wheel ALL=(ALL) ALL,!SHUTDOWN #修改
Defaults logfile=/var/log/sudo.log

5 禁用selinux

grep -i ^selinux /etc/selinux/config
SELINUX=enforcing
SELINUXTYPE=targeted

sed -i ‘/^SELINUX/s/enforcing/disabled/g‘ /etc/selinux/config

grep -i ^selinux /etc/selinux/config
SELINUX=disabled
SELINUXTYPE=targeted

getenforce
Enforcing

reboot

6 关闭防火墙安装

iptablessystemctl stop firwalld
systemctl disable firwalld
yum install iptables-services -y #安装

7修改主机名

hostnamectl set-hostname hequan.com

hostname
hequan.com

8 查看并管理服务

systemctl -t service
systemctl list-unit-files -t service

9 设置字符集

echo $LANG
zh_CN.UTF-8
 vi /etc/locale.conf
LANG="en_US.UTF-8"
 source /etc/locale.conf

10 yum

yum install gcc cmake bzip2-devel curl-devel db4-devel libjpeg-devel libpng-devel freetype-devel libXpm-devel gmp-devel libc-client-devel openldap-devel unixODBC-devel postgresql-devel sqlite-devel aspell-devel net-snmp-devel libxslt-devel libxml2-devel pcre-devel mysql-devel pspell-devel libmemcached libmemcached-devel zlib-devel vim wget lrzsz tree

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
cd /etc/yum.repos.d/
wget http://mirrors.163.com/.help/CentOS7-Base-163.repo
yum clean all
yum makecache
其他
yum -y install yum-plugin-priorities ##安装优先级插件
sed -i -e "s/\]$/\]\npriority=1/g" /etc/yum.repos.d/CentOS-Base.repo ##设置基本yum源的优先级为1
yum -y install epel-release ##安装epel源
sed -i -e "s/\]$/\]\npriority=5/g" /etc/yum.repos.d/epel.repo ##设置优先级为5
sed -i -e "s/enabled=1/enabled=0/g" /etc/yum.repos.d/epel.repo ##禁用epel源
yum -y install http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el7.rf.x86_64.rpm ##安装rpmforge的源
sed -i -e "s/\]$/\]\npriority=10/g" /etc/yum.repos.d/rpmforge.repo ##设置优先级为10
sed -i -e "s/enabled = 1/enabled = 0/g" /etc/yum.repos.d/rpmforge.repo ##禁用yum源
使用方法：yum --enablerepo=rpmforge install [Package]

11 配置sshd

sed -i -e ‘49s/^#//g‘ /etc/ssh/sshd_config ##启用49行配置
sed -i -e ‘49s/yes/no/g‘ /etc/ssh/sshd_config ##禁止root使用ssh登录
sed -i -e ‘129s/#/ /g‘ /etc/ssh/sshd_config ##禁止UseDNS
sed -i -e ‘129s/yes$/no/g‘ /etc/ssh/sshd_config
sed -i ‘/^GSS/s/yes/no/g‘ /etc/ssh/sshd_config ##禁用GSSAPI认证加快登录速度
systemctl restart sshd ##重新启动服务
systemctl enable sshd ##设置为开机启动
systemctl status sshd ##查看状态
● sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
Active: active (running) since 一 2016-06-06 00:16:26 CST; 1min 3s ago
12 加大打开文件数的限制（open files）
ulimit -n
ulimit -a
vi /etc/security/limits.conf
最后添加
* soft nofile 1024000
* hard nofile 1024000
hive - nofile 1024000
hive - nproc 1024000

用户进程限制

sed -i ‘s#4096#65535#g‘ /etc/security/limits.d/20-nproc.conf #加大普通用户限制 也可以改为unlimited
 egrep -v "^$|^#" /etc/security/limits.d/20-nproc.conf
* soft nproc 65535
root soft nproc unlimited

reboot

13 优化内核

cat /etc/sysctl.conf
#CTCDN系统优化参数
#关闭ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
#决定检查过期多久邻居条目
net.ipv4.neigh.default.gc_stale_time=120
#使用arp_announce / arp_ignore解决ARP映射问题
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce=2
net.ipv4.conf.lo.arp_announce=2
# 避免放大攻击
net.ipv4.icmp_echo_ignore_broadcasts = 1
# 开启恶意icmp错误消息保护
net.ipv4.icmp_ignore_bogus_error_responses = 1
#关闭路由转发
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
#开启反向路径过滤
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
#处理无源路由的包
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
#关闭sysrq功能
kernel.sysrq = 0
#core文件名中添加pid作为扩展名
kernel.core_uses_pid = 1
# 开启SYN洪水攻击保护
net.ipv4.tcp_syncookies = 1
#修改消息队列长度
kernel.msgmnb = 65536
kernel.msgmax = 65536
#设置最大内存共享段大小bytes
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
#timewait的数量，默认180000
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
#每个网络接口接收数据包的速率比内核处理这些包的速率快时，允许送到队列的数据包的最大数目
net.core.netdev_max_backlog = 262144
#限制仅仅是为了防止简单的DoS 攻击
net.ipv4.tcp_max_orphans = 3276800
#未收到客户端确认信息的连接请求的最大值
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
#内核放弃建立连接之前发送SYNACK 包的数量
net.ipv4.tcp_synack_retries = 1
#内核放弃建立连接之前发送SYN 包的数量
net.ipv4.tcp_syn_retries = 1
#启用timewait 快速回收
net.ipv4.tcp_tw_recycle = 1
#开启重用。允许将TIME-WAIT sockets 重新用于新的TCP 连接
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
#当keepalive 起用的时候，TCP 发送keepalive 消息的频度。缺省是2 小时
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
#允许系统打开的端口范围
net.ipv4.ip_local_port_range = 1024 65000
#修改防火墙表大小，默认65536
net.netfilter.nf_conntrack_max=655350
net.netfilter.nf_conntrack_tcp_timeout_established=1200
# 确保无人能修改路由表
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0

sysctl -p #生效

14 时间设置

yum install chrony
vi /etc/chrony.conf
1 server 0.centos.pool.ntp.org
2 server 3.europe.pool.ntp.org
systemctl enable chronyd.service
systemctl start chronyd.service
timedatectl set-timezone Asia/Shanghai
timedatectl set-time "2018-01-21 11:50:00"（可以只修改其中一个）修改日期时间
timedatectl 查看时间状态
chronyc sources -v 查看时间同步源
chronyc sourcestats -v