Linux 系统初始化

CentOS 7.9 系统初始化

# 内网用户关闭安全组及防火墙
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

/etc/init.d/iptables stop
/etc/init.d/iptables stop
chkconfig iptables off

systemctl stop firewalld
systemctl disable firewalld

# 配置系统最大进程数
echo '* - nofile 65535 ' >>/etc/security/limits.conf

# 更换软件源
sed -e "s|^mirrorlist=|#mirrorlist=|g" \
    -e "s|^#baseurl=http://mirror.centos.org/centos/\$releasever|baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/7.9.2009|g" \
    -e "s|^#baseurl=http://mirror.centos.org/\$contentdir/\$releasever|baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/7.9.2009|g" \
    -i.bak \
    /etc/yum.repos.d/CentOS-*.repo
    
yum makecache

# 安装并配置时间同步
yum -y install ntpdate
touch /var/spool/cron/root
echo '*/5 * * * * /usr/sbin/ntpdate ntp.aliyun.com >/dev/null 2>&1' >>/var/spool/cron/root

crontab -l
*/5 * * * * /usr/sbin/ntpdate ntp.aliyun.com >/dev/null 2>&1

# 安装系统扩展包
yum install epel-release.noarch -y

# 重启系统
reboot

# 查看优化效果
getenforce
systemctl status firewalld
iptables -L
ulimit -n
crontab -l

# 手动执行时间同步
/usr/sbin/ntpdate ntp.aliyun.com

CentOS 8.1 系统初始化

# 内网用户关闭安全组及防火墙
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

/etc/init.d/iptables stop
/etc/init.d/iptables stop
chkconfig iptables off

systemctl stop firewalld
systemctl disable firewalld

# 配置系统最大进程数
echo '* - nofile 65535 ' >>/etc/security/limits.conf

# 更换软件源
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.cloud.tencent.com/repo/centos8_base.repo
yum makecache

# 安装常用软件
yum install epel-release.noarch lrzsz wget nano vim git -y
yum install ftp lrzsz nmap tree dos2unix nc sysstat -y
dnf upgrade libmodulemd -y

# 安装并配置时间同步
dnf install -y chrony

# 手动同步
chronyd -q 'server ntp.aliyun.com iburst'

# 配置开机启动
systemctl enable chronyd
systemctl start chronyd

# Chrony 配置
vi /etc/chrony.conf
server ntp.aliyun.com iburst
# pool 2.centos.pool.ntp.org iburst

# Chrony 重启生效
systemctl restart chronyd

# 查看同步状态
chronyc tracking

# 查看同步的时间服务器
chronyc sources

# 重启系统
reboot

# 查看优化效果
getenforce
ulimit -n
systemctl status firewalld
iptables -L

Ubuntu 24.04 系统初始化

# 手动指定静态IP地址
cat /etc/netplan/50-cloud-init.yaml
network:
    ethernets:
        ens18:
            addresses:
            - 192.168.1.9/24
            nameservers:
                addresses:
                - 180.184.1.1
                search: []
            routes:
            -   to: default
                via: 192.168.1.1
    version: 2
    
sudo netplan apply

# 用户酌情开启root权限
sudo passwd root

# 系统更新
sudo apt update

# 安装ssh服务
sudo apt install openssh-server

# 配置使用root远程ssh
sudo vi /etc/ssh/sshd_config
LoginGraceTime 2m
PermitRootLogin yes
#PermitRootLogin prohibit-password
StrictModes yes

# 两种重启服务的方式
sudo systemctl restart sshd
sudo systemctl restart ssh.service

# 修改时区
tzselect
ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime