How to Convert NetworkManager to networkd

This post will describe how to convert NetworkManager to networkd.

I am using Fedora Workstation 24 image. If you are using fedora or projectatomic cloud images you can use networkd there.

Switching from NetworkManager to networkd:

We need to make sure that NetworkManager and networkd don’t start on reboot.

# systemctl disable NetworkManager
# systemctl disable network

Now Ensure that systemd-networkd starts on the next boot:

# systemctl enable systemd-networkd

Enable the resolver and make a symlink:

# systemctl enable systemd-resolved
# systemctl start systemd-resolved
# rm -f /etc/resolv.conf
# ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf

Configure your network interfaces in /etc/systemd/network and then reboot.

Some sample use cases for systemd-networkd and example configurations are below:

Simple DHCP on single interface

For an interface eth0, a single .network file is needed

# cat /etc/systemd/network/eth0.network
[Match]
Name=eth0

[Network]
DHCP=yes

Bridging

Here we have eth0 and we want to add it to a bridge. This could be handy for servers where you want to build containers or virtual machines and attach them to the network bridge.

We will start with setting up bridge interface br0.

# cat /etc/systemd/network/br0.netdev
[NetDev]
Name=br0
Kind=bridge

Let’s configure the network for the bridge

# cat /etc/systemd/network/br0.network
[Match]
Name=br0

[Network]
IPForward=yes
DHCP=yes

The IPForward=yes will take care of the systemctl forwarding setting for us (net.ipv4.conf.br0.forwarding = 1) automatically when the interface comes up.
Now take ethernet adapter and add it to bridge

# cat /etc/systemd/network/eth0.network
[Match]
Name=eth0

[Network]
Bridge=br0

Now reboot the system and it will come up with eth0 as a port on br0.

Bonding

Let’s configure a bonding interface which is similar to that of a bridge. Start by setting up individual network adapters.

# cat /etc/systemd/network/ens9f0.network
[Match]
Name=ens9f0
 
[Network]
Bond=bond1

# cat /etc/systemd/network/ens9f1.network
[Match]
Name=ens9f1

[Network]
Bond=bond1

Create network device for the bond

# /etc/systemd/network/bond1.netdev
[NetDev]
Name=bond1
Kind=bond

[Bond]
Mode=802.3ad
TransmitHashPolicy=layer3+4
MIIMonitorSec=1s
LACPTransmitRate=fast

Add networking to the device

# /etc/systemd/network/bond1.network
[Match]
Name=bond1
 
[Network]
DHCP=yes
BindCarrier=ens9f0 ens9f1

The BindCarrier is optional but recommended. It gives systemd-networkd the hint that if both bonded interfaces are offline, it should remove the bond configuration until one of the interfaces comes up again.

Check Status

Output from systemd-netword will appear in system journal. The networkctl command allows to check your network devices at a glance.

Here’s an example of the network setup we just created:

Further Reading: http://fedoracloud.readthedocs.io/en/latest/networkd.html