更换国内APT源

cat > /etc/apt/sources.list << EOF
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
EOF

安装常用软件

apt update && apt install -y iproute2 ntpdate tcpdump telnet traceroute nfs-kernel-server lrzsz tree openssl libssl-dev libpcre3 libpcre3-dev zlib1g-dev ntpdate tcpdump telnet traceroute gcc openssh-server lrzsz tree openssl libssl-dev libpcre3 libpcre3-dev zlib1g-dev ntpdate tcpdump telnet traceroute iotop unzip zip

停用常见服务

systemctl stop apparmor &&  systemctl disable apparmor #停用selinux
systemctl stop ufw && systemctl disable ufw #停用防火墙

内核参数优化

cat >> /etc/sysctl.conf << EOF
vm.max_map_count=262144
# Controls source route verification
net.ipv4.conf.default.rp_filter = 1
net.ipv4.ip_nonlocal_bind = 1
net.ipv4.ip_forward = 1
# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0
# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 0
# Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid = 1
# Controls the use of TCP syncookies
net.ipv4.tcp_syncookies = 1
# Controls the default maxmimum size of a mesage queue
kernel.msgmnb = 65536
# # Controls the maximum size of a message, in bytes
kernel.msgmax = 65536
# Controls the maximum shared segment size, in bytes
kernel.shmmax = 68719476736
# # Controls the maximum number of shared memory segments, in pages
kernel.shmall = 4294967296
# TCP kernel paramater
net.ipv4.tcp_mem = 786432 1048576 1572864
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_sack = 1
# socket buffer
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 20480
net.core.optmem_max = 81920
# TCP conn
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_syn_retries = 3
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_retries2 = 15
# tcp conn reuse
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_tw_reuse = 0
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_max_tw_buckets = 20000
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syncookies = 1
# keepalive conn
net.ipv4.tcp_keepalive_time = 300
net.ipv4.tcp_keepalive_intvl = 30
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.ip_local_port_range = 10001 65000
# swap
vm.overcommit_memory = 0
vm.swappiness = 10
#net.ipv4.conf.eth1.rp_filter = 0
#net.ipv4.conf.lo.arp_ignore = 1
#net.ipv4.conf.lo.arp_announce = 2
#net.ipv4.conf.all.arp_ignore = 1
#net.ipv4.conf.all.arp_announce = 2
EOF

修改文件连接数

cat >> /etc/security/limits.conf << EOF
root soft core unlimited
root hard core unlimited
root soft nproc 1000000
root hard nproc 1000000
root soft nofile 1000000
root hard nofile 1000000
root soft memlock 32000
root hard memlock 32000
root soft msgqueue 8192000
root hard msgqueue 8192000

* soft core unlimited
* hard core unlimited
* soft nproc 1000000
* hard nproc 1000000
* soft nofile 1000000
* hard nofile 1000000
* soft memlock 32000
* hard memlock 32000
* soft msgqueue 8192000
* hard msgqueue 8192000
EOF

常用设置

启用root登录

cat >> /etc/ssh/sshd_config << EOF
PermitRootLogin yes
PasswordAuthentication yes
EOF
systemctl restart sshd

时区设置：

rm -rf /etc/localtime 
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

Docker安装

安装必要的一些系统工具

apt-get update
apt-get -y install apt-transport-https ca-certificates curl software-properties-common

安装GPG证书

curl -fsSL https://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg | sudo apt-key add -

写入软件源信息

sudo add-apt-repository "deb [arch=amd64] https://mirrors.aliyun.com/docker-ce/linux/ubuntu $(lsb_release -cs) stable"

更新并安装Docker-CE

sudo apt-get -y update
sudo apt-get -y install docker-ce

安装指定版本的Docker-CE

查找Docker-CE的版本:

apt-cache madison docker-ce
#docker-ce | 17.03.1~ce-0~ubuntu-xenial | https://mirrors.aliyun.com/docker-ce/linux/ubuntu xenial/stable amd64 Packages
#docker-ce | 17.03.0~ce-0~ubuntu-xenial | https://mirrors.aliyun.com/docker-ce/linux/ubuntu xenial/stable amd64 Packages

安装指定版本的Docker-CE:

# Step 2: 安装指定版本的Docker-CE: (VERSION例如上面的17.03.1~ce-0~ubuntu-xenial)
apt-get -y install 17.03.1~ce-0~ubuntu-xenial

常用命令

网络相关

#重载网卡配置
networkctl reload
#查看配网卡信息
networkctl status
#配置网卡信息
vim /etc/netplan/00-installer-config.yaml
#配置实例：
network:
  ethernets:
    enp0s3:
      addresses:
      - 192.168.101.51/24
      gateway4: 192.168.101.254
      nameservers:
        addresses:
          - 223.5.5.5
          - 223.6.6.6
  version: 2
#网卡配置生效
netplan apply

常用服务：

nfs安装：

#安装服务：
apt install nfs-kernel-server
#开机启动
systemctl enable nfs-kernel-server
#编辑共享文件夹
vim /etc/exports
/data/nfs *(rw,sync,no_root_squash,no_subtree_check)
#rw 允许读写
#sync 文件同时写入硬盘和内存
#no_subtree_check 即使输出目录是一个子目录，nfs服务器也不检查其父目录的权限，这样可以提高效率
#no_root_squash 不压缩root用户权限
#显示nfs共享目录
showmount -e 192.168.1.51
# Export list for 192.168.1.51
# /data/nfs *

常见问题：

Ubuntu修改国内源之后报错 Certificate verification failed: The certificate is NOT trusted

cd /tmp
wget http://archive.ubuntu.com/ubuntu/pool/main/c/ca-certificates/ca-certificates_20210119~20.04.2_all.deb
dpkg -i ./ca-certificates_20210119~20.04.2_all.deb

系统克隆后，修改网卡UUID地址：

sed -i "/UUID/c UUID=$(uuidgen)" /etc/sysconfig/network-scripts/ifcfg-ens192