Configure KVM Bridge Network using netplan

On Ubuntu 20.04 server we have the following network configuration

root@mail:~# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp2s0:  mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether d8:cb:8a:e3:c7:c9 brd ff:ff:ff:ff:ff:ff
    inet 37.157.249.137/32 scope global enp2s0
       valid_lft forever preferred_lft forever
    inet6 fe80::dacb:8aff:fee3:c7c9/64 scope link
       valid_lft forever preferred_lft forever
root@mail:~#

“netplan get all” command show following

netplan config file has the following

root@mail:~# cat /etc/netplan/01-netcfg.yaml
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    enp2s0:
      addresses: [ 37.157.249.137/32 ]
      nameservers:
          search: [ venus.dedi.server-hosting.expert ]
          addresses:
              - "8.8.8.8"
              - "1.1.1.1"
      routes:
      - to: 0.0.0.0/0
        via: 37.157.249.129
        on-link: true

root@mail:~#

Before you can use bridge in netplan, you need to install bridge-utils

apt-get install bridge-utils

To configure bridge networking, modify the file as follows

network:
    version: 2
    renderer: networkd
    ethernets:
        enp2s0:
            dhcp4: no
            dhcp6: no
    bridges:
        br0:
            dhcp4: no
            dhcp6: no
            interfaces: [enp2s0]
            addresses: [ 37.157.249.137/32 ]
            nameservers:
                addresses:
                    - "8.8.8.8"
                    - "1.1.1.1"
            routes:
            -   to: 0.0.0.0/0
                via: 37.157.249.129
                on-link: true

To check if there is any error in netplan configuration, run

netplan generate

To test the configuration, run

netplan try