Re: systemd-nspawn networking inside VirtualBox VM

[Didar Hossain <didar@purlo.in>]

On Tue, Jul 07, 2020 at 06:05:14PM +0200, john doe wrote:
> On 7/7/2020 3:13 PM, Didar Hossain wrote:
> > Hi,
> > 
> > TL;DR
> > How to get systemd-nspawn containers networking so that they can talk to each
> > other, the host and the internet inside a Buster VM? VirtualBox on Windows 10
> > which has internet connectivity via a wireless interface.
> > 
> > 
> > 
> > I am running a Buster VM with hand picked minimal packages, networking is
> > configured simply using interfaces(5) file with DHCP. I have configured a
> > "NatNetwork" on VirtualBox which allows the VMs to connect to each other and the
> > internet. I was wondering if I can do similar thing with containers inside the
> > buster VM.
> > 
> > I used `debbootstrap' to have a template directory of buster under
> > "/opt/templates/buster". I then simply copy the directory tree over to
> > "/var/lib/machines". I tried a few networking options of `systemd-nspawn', but
> > since I am not well educated about macvlan, ipvlan, I could not get the
> > networking working at all. I would like to avoid using
> > "systemd-networkd/systemd-resolvd" especially on the Buster host - using those
> > it seems should make everything work automagically.
> > 
> > If it works then I will be able to test my Dovecot/Exim setup easily in such
> > throwaway containers. I currently do testing using VMs.
> > 
> > Does anyone have experience in having this kind of scenario working?
> > 
> 
> For testing purposes, I use in a Buster VM systemd-container.
> That is if your VM has internet access the containers will also get
> internet access .
> 
> For sake of simplicity, I would strongly suggest you to use in the VM
> systemd-networkd to get the networking working between the containers
> and the VM.

I finally gave in and tried things with systemd-networkd - it worked. It seems
the trick is mostly the way routing is setup, "ip route" shows multiple line
output which is difficult to understant unless you know how to work iproute2
advanced routing.

> $ debootstrap --include=systemd-container
> 
> You need the above debootstrap pkg for systemd-networkd to work in the
> container.
> 
> Then in the VM and in eatch container, simply enable systemd-networkd.
> 
> 
> If you realy want to do the networking yourself, you will need to create
> the bridge based on the examples found in '/lib/systemd/network'.
> 
> --
> John Doe
> 

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