creating two net bridges on one phisical computer

I have two network cards on my computer. I want to create two net bridges with netplan to add this bridged networks to kernel based virtual machines (KVM). Both network cards are connected to the same router which has access to Internet.

I have the following network configuration using netplan:

network:
    version: 2
    renderer: networkd
    ethernets:
        eth-host0:
          match:
            macaddress: xxx:97:02
          dhcp4: false
          dhcp6: false
        eth-host1:
          match:
            macaddress: xxx:08:61
          dhcp4: false
          dhcp6: false
    bridges:
        br0:
          interfaces: [eth-host0]
          addresses: [192.168.0.9/24]
          gateway4: 192.168.0.1
          mtu: 1500
          nameservers:
            addresses: [8.8.8.8]
          parameters:
            stp: true
            forward-delay: 4
          dhcp4: true
          dhcp6: false
        br1:
          interfaces: [eth-host1]
          addresses: [192.168.1.9/24]
          gateway4: 192.168.0.1
          mtu: 1500
          nameservers:
            addresses: [8.8.8.8]
          parameters:
            stp: true
            forward-delay: 4
          dhcp4: true
          dhcp6: false 

when I issue command

sudo netplan apply

I got the following error "Problem encountered while validating default route consistency.Please set up multiple routing tables and use routing-policy instead. Error: Conflicting default route declarations for IPv4 (table: main, metric: default), first declared in br0 but also in br1"

If I delete default gateway, than apply passes but I do not have any networks on my virtual machine.

How do I properly configure two bridges on the same computer?

Solution 1:

I'm not a Netplan expert but you could try to remove the gateway4: 192.168.0.1 from br1 (but leave it on br0).

If that doesn't work, try to add this to br1:

routes:
  - to: 0.0.0.0/0
    via: 192.168.0.1
    table: 101
routing-policy:
  - from: 192.168.1.9/24
    table: 101

BTW before running netplan apply run netplan generate. Then you will se the errors before applying. I have lost connections to the server a couple of times because of simple mistakes :-)

Often I also have to reboot for the changes to fully apply.