Ubuntu 18 is the OS that adds a NIC to a server instance in Sakura's cloud and assigns a local IP.

Create a server in Sakura's cloud, add a NIC and assign a local IP

When you want to have such a configuration

With a server that connects to the Internet Separate servers that cannot be connected to the Internet. I don't know what kind of attack will come when I connect to the Internet. Therefore, if you want to prevent the server containing important data from being directly connected to the Internet.

Server A to connect to the Internet needs two NICs

What is a NIC? Network interface card Connect NIC1 to the interface Connect NIC2 to LAN

Actual configuration

Create a server. Assign a global IP to the NIC when it is created. After creating the server instance, add a NIC and connect to the switch. The switch address is 192.168.101.1 and the VPN router has been set. Then connect to the VPN with a MacBook Pro etc. and log in to the Ubuntu server.

This time I recorded the procedure to add a NIC and set the local IP address 192.168.101.20.

Setting procedure Confirm that the eth1 device has been created

Execute the command. ip addr To check the address allocation status

ipconfig -a Then, make sure that the eth1 device exists.

netplan It seems that the network is set up from Ubuntu 18 with something called netplan. See below for details. https://wiki.ubuntu.com/Netplan https://netplan.io/

Make a backup

sudo cp -p /etc/netplan/01-netcfg.yaml /home/ubuntu/01-netcfg.yaml.bkup

If you make a mistake in the network settings, you will not be able to log in with SSH. Make a backup so that you can restore it. Hmm? How do I get the settings back when I can't log in with SSH? At that time, let's work using Sakura's cloud console. https://manual.sakura.ad.jp/cloud/server/console.html

Edit 01-netcfg.yaml

sudo vi /etc/netplan/01-netcfg.yaml And edit with the vi editor. You can also use the nano editor.

01-netcfg.yaml after change

network: 
  ethernets: 
    eth0: 
      addresses: 
        - 153.125.512.30/24
      dhcp4: 'no'
      dhcp6: 'no'
      gateway4: 153.125.512.1
      nameservers: 
        addresses: 
          - 133.242.0.3
          - 133.242.0.4
        search: 
          - localdomain
    eth1:
      addresses:
        - 192.168.101.20/24

  renderer: networkd
  version: 2

The part to be added below.

• Check if the device name such as eth1: is the same as the name of ifconfig -a.

    eth1:
      addresses:
        - 192.168.101.20/24

Reflect the settings

sudo netplan apply To check if the address is reflected in ifconfig.

Try rebooting

sudo shutdown -r now Reboot with, log in with SSH and make sure the network settings are enabled with ifconfig. If you make a mistake at this time, you may not be able to log in with SSH. In that case, use the console to restore the settings.

This is the first time I learned about netplan. I'm not familiar with it, so it may be wrong. Masakari is welcome.