how to make sure bridge interface is up with netplan after reboot

[Tom H]

On Fri, Mar 9, 2018 at 10:34 AM, mabi via ubuntu-users
<ubuntu-users at lists.ubuntu.com> wrote:
>
> I am using Ubuntu 17.10 and therefore Netplan which I have configured
> a bridge for a specific network interface for my Xen virtual machines.
> Unfortunately when I reboot the server that bridge interface is in
> state DOWN so that I have to manually set it up using "ip link set
> xenbr1 up" command. Now does anyone know how to make sure netplan
> brings my bridge interface automatically up at reboot?
>
> Here is the relevant part of my netplan netcfg.yaml file:
>
> network:
>   version: 2
>   renderer: networkd
>   ethernets:
>     eno3:
>       dhcp4: no
>   bridges:
>     xenbr1:
>       interfaces: [eno3]
>       dhcp4: no
>       parameters:
>         stp: no
>         forward-delay: 0

You have "dhcp4: no" and no "addresses:" defined so I wouldn't expect
xenbr1 to be "UP".

What do the "*.network" files in "/run/systemd/" contain?