Tools/Linux_reinstall/Ubuntu/CloudInit/ipv4_static_interfaces.cfg

#cloud-config
# CLOUD_IMG: This file was created/modified by the Cloud Image build process

# configure cloud-init for NoCloud
datasource_list: [ NoCloud, None ]

# configure repository
system_info:
  package_mirrors:
    - arches: [i386, amd64]
      failsafe:
        primary: http://targetLinuxMirror/ubuntu
        security: http://security.ubuntu.com/ubuntu
    - arches: [arm64, armel, armhf]
      failsafe:
        primary: http://targetLinuxMirror/ubuntu-ports
        security: http://targetLinuxMirror/ubuntu-ports

# configure hostname
hostname: HostName

# configure localization
locale: en_US.UTF-8

# configure timezone
timezone: TimeZone

# configure root user
users:
  - name: root
    lock_passwd: false
    shell: /bin/bash

chpasswd:
  expire: false
  list: |
    root:tmpWORD
  users:
    - name: root
      password: tmpWORD
      type: text

# configure network
# Adding "on-link: true" for each routes is recommended for the "routes(gateway)" menu in network config file of netplan otherwise netplan will calculate whether the gateway is in range of IP/prefix, if not, the network can't work normally.
# Despite adding "on-link: true" is only necessary for the situation of irregular IPv4 configs(public IPv4 address with the a private IPv4 gateway or gateway is also a public address but from A class is different from the former),
# this setting won't affect the normal IPv4 configurations.
# So in order to considering the most general availability of the various complex environments of the networkings, we should add "on-link" in all items which need to be configurated manually cloud-init files.
# Reference: https://netplan.readthedocs.io/en/latest/netplan-yaml/#default-routes
network:
  version: 2
  ethernets:
    networkAdapter:
      dhcp4: false
      addresses: [IPv4/ipPrefix]
      routes:
        - to: default
          via: GATE
          on-link: true
      nameservers:
        addresses: [ipDNS1, ipDNS2]

# later commands
# Replace ssh port, permit root user login by password, enable sshd service.
# Disable kernel need to restart: https://askubuntu.com/questions/1349884/how-to-disable-pending-kernel-upgrade-message
# Install some common components.
# Configure vim for more convenient to use.
# Rename netplan config file.
# Configure fail2ban.
# Delete cloud-init config file itself and disable it permanently after first execution.
runcmd:
  - sed -ri 's/^#?Port.*/Port sshPORT/g' /etc/ssh/sshd_config
  - sed -ri 's/^#?PermitRootLogin.*/PermitRootLogin yes/g' /etc/ssh/sshd_config
  - sed -ri 's/^#?PasswordAuthentication.*/PasswordAuthentication yes/g' /etc/ssh/sshd_config
  - update-rc.d ssh enable
  - ssh-keygen -A
  - /etc/init.d/ssh restart
  - sed -i 's/#$nrconf{restart} = '"'"'i'"'"';/$nrconf{restart} = '"'"'a'"'"';/g' /etc/needrestart/needrestart.conf
  - sed -i "s/#\$nrconf{kernelhints} = -1;/\$nrconf{kernelhints} = -1;/g" /etc/needrestart/needrestart.conf
  - apt update
  - apt install dnsutils fail2ban file lrzsz net-tools vim wget -y
  - sed -ri 's/set compatible/set nocompatible/g' /etc/vim/vimrc.tiny
  - sed -ri '/set nocompatible/a\set backspace=2' /etc/vim/vimrc.tiny
  - mv /etc/netplan/50-cloud-init.yaml /etc/netplan/20-netcfg.yaml
  - netplan apply
  - sed -i '/^\[Definition\]/a allowipv6 = auto' /etc/fail2ban/fail2ban.conf
  - sed -ri 's/^backend = auto/backend = systemd/g' /etc/fail2ban/jail.conf
  - update-rc.d fail2ban enable
  - /etc/init.d/fail2ban restart
  - rm -rf /etc/cloud/cloud.cfg.d/99-fake_cloud.cfg
  - touch /etc/cloud/cloud-init.disabled