Automation with systemd-networkd
This section assumes you have a properly working systemd setup prior to attempting.
We’ll be using our favorite text editor to create a few configuration files that a systemctl service can use to automatically create and assign our bridge an IP address! This makes it much easier to have a bridge that persists through reboots, while this can be done manually via the instructions in the video, there is also a great section containing steps for the automation part, and that’s what we’ll focus on here for our production use.
Let’s begin by checking if systemd-networkd is enabled or running. If you know you already have this set up, please back up your current configuration files in preparation for the bridge configuration.
sudo systemctl status systemd-networkd
[liveuser@eos-2023.03.26 ~]$ sudo systemctl status systemd-networkd
○ systemd-networkd.service - Network Configuration
Loaded: loaded (/usr/lib/systemd/system/systemd-networkd.service; disabled; preset: enabled)
Active: inactive (dead)
TriggeredBy: ○ systemd-networkd.socket
Docs: man:systemd-networkd.service(8)
[liveuser@eos-2023.03.26 ~]$
On this system we can see that it’s disabled and inactive. Perfect, let’s get started using our favorite text editor! For this example we’ll use Nano.
cd /etc/systemd/network
We’ll begin with the first file br.netdev which will define the Bridge interface.
sudo nano br.netdev
[NetDev]
Name=br0
Kind=bridge
Next, let’s create the file 1-br0-bind.network which will bind our ethernet to the bridge interface it will create. Please note the * is a wildcard. This means it will autocomplete and work on any interface starting with enp. Since you got the name last page, you can write it specifically down, or use a wildcard as seen here.
sudo nano 1-br0-bind.network
[Match]
Name=enp*
[Network]
Bridge=br0
Now we’re going to create our final file 2-br0-dhcp.network. This is responsible for telling br0 it’s to get an IP address assigned to it by DHCP using IPV4.
sudo nano 2-br0-dhcp.network
[Match]
Name=br0
[Network]
DHCP=ipv4
Our setup is now complete! To begin tesing, let’s go ahead and enable systemd-networkd, as well as starting the service to see if our internet connection returns.
sudo systemctl enable systemd-networkd
sudo systemctl start systemd-networkd
You can check the logs to see if it properly worked by checking the status.
sudo systemctl status systemd-networkd
Example output of a success:
[liveuser@eos-2023.03.26 BridgeNetworking]$ sudo systemctl status systemd-networkd
● systemd-networkd.service - Network Configuration
Loaded: loaded (/usr/lib/systemd/system/systemd-networkd.service; enabled; preset: enabled)
Active: active (running) since Fri 2023-07-14 03:29:43 CDT; 1min 26s ago
TriggeredBy: ● systemd-networkd.socket
Docs: man:systemd-networkd.service(8)
Main PID: 3512 (systemd-network)
Status: "Processing requests..."
Tasks: 1 (limit: 9403)
Memory: 3.7M
CPU: 709ms
CGroup: /system.slice/systemd-networkd.service
└─3512 /usr/lib/systemd/systemd-networkd
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: Enumeration completed
Jul 14 03:29:43 EndeavourOS systemd[1]: Started Network Configuration.
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: enp0s1: Configuring with /etc/systemd/network/1-br0-bind.network.
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: br0: Configuring with /etc/systemd/network/2-br0-dhcp.network.
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: br0: Link UP
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: enp0s1: Link UP
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: enp0s1: Gained carrier
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: br0: Gained carrier
Jul 14 03:29:43 EndeavourOS systemd-networkd[3512]: br0: DHCPv4 address 192.168.0.5/24, gateway 192.168.0.1 acquired from 192.168.0.1
Jul 14 03:29:44 EndeavourOS systemd-networkd[3512]: br0: Gained IPv6LL
[liveuser@eos-2023.03.26 BridgeNetworking]$