Setting a static IP address on Ubuntu 18.04 using Netplan

Netplan is the default network manager since Ubuntu 17.10. No longer do you edit the /etc/network/interfaces file, ohh the memories. Now we get to work with YAML, which is a nice change, and then the actual configuration is rendered from this configuration file.

I have already ssh’d into my system, this time I used Ubuntu’s ability to import my saved public key from launchpad.net based on my user account, this was quite slick, I might try that again sometime. This system is going to be for testing out the Helk, a pre-configured and easily installable ELK Stack. Let’s jump in.

Determine your interface device

First, I determine my current network device with the command ip link, see the output below. The eth0 is the virtual adapter (I am using XCP-NG

jp@elk:~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether b6:7d:64:89:ce:9e brd ff:ff:ff:ff:ff:ff

Edit the Netplan config

The config files for Netplan are in the /etc/netplan directory, but in my installation there is no obvious network config, just the one created by the installer called 00-installer-config.yaml. So, I created one called 01-netcfg.yaml, since that is what I was expecting to see, then I renamed the old one to get it out of the way. Finally, I ran sudo netplan apply to make sure it worked. In the end, I could have just left the filename the same, or renamed it, but sometimes we learn more from our mistakes than getting it right the first time.

jp@elk:~$ sudo cp /etc/netplan/00-installer-config.yaml /etc/netplan/01-netcfg.yaml
[sudo] password for jp:
jp@elk:~$ sudo mv /etc/netplan/00-installer-config.yaml /etc/netplan/00-installer-config.yaml.bak
sudo netplan apply
... nothing bad happened! ¯\_(ツ)_/¯

Now we need to edit the plan, to do this I am using Vim, but you do you. Below is what my unmodified Netplan looks like.

jp@elk:/etc/netplan$ cat 01-netcfg.yaml
# This is the network config written by 'subiquity'
network:
  ethernets:
    eth0:
      dhcp4: true
  version: 2

Let’s jazz that up with some static goodness. Here is my config with a static address. Then when I am reasonably sure this is good, I run sudo netplan apply.

jp@elk:/etc/netplan$ cat 01-netcfg.yaml
# This is the network config written by 'JP'
network:
  ethernets:
    eth0:
      dhcp4: false
      addresses:
        - 10.1.1.70/24
      gateway4: 10.1.1.1
      nameservers:
        addresses:
          - 1.1.1.3
          - 1.0.0.3
  version: 2

Of course, my ssh session is immediately abandoned… I should have run screen first. I was able to reconnect with the new IP address. So, it worked, and now I have a static IP address on this lab system. NOICE!