Adding a network interface

Adding a network interface

[Konrad Hinsen]

Dear Guixers,

I have started to play with GuixSD in a virtual machine, but I quickly 
got stuck. My starting point is the supplied "bare bones" setup, which 
works fine with only trivial modifications such as the disk device name 
and the user accounts to be created.

My virtual machine has two network interfaces, one for connections to 
the outside world and one for connections to/from the host (that's how 
VirtualBox works). The first one gets configured automatically via DHCP, 
presumably via (dhcp-client-service). The second one must be configured 
statically. After some exploration, I added

   (static-networking-service "enp0s8" ...)

to the list of services. No chance:

   service "networking" provided more than once

That must be because "lo" is already configured in %base-services. But 
the documentation explicitly says that I can call 
static-networking-service multiple times for multiple interfaces!

After a look at the source code for service management, I tried

   (modify-services %base-services
      (static-networking-service-type
         interfaces => (cons (static-networking-service "enp0s8" ...)
                             interfaces)))

This yields an error message from static-networking-shepherd-service 
about concerning "no matching pattern", which suggests that I haven't 
read enough of the source code to get this right. Back to the source 
code, and another try:

   (modify-services %base-services
      (static-networking-service-type
         interfaces => (cons (static-networking (interface "enp0s8") ...)
                             interfaces)))

Now I am back to: service "networking" provided more than once. So I am 
giving up... What's the solution to this puzzle?

Konrad.

Re: Adding a network interface

[Ricardo Wurmus]

Hi Konrad,

> My virtual machine has two network interfaces, one for connections to 
> the outside world and one for connections to/from the host (that's how 
> VirtualBox works). The first one gets configured automatically via DHCP, 
> presumably via (dhcp-client-service). The second one must be configured 
> statically. After some exploration, I added
>
>    (static-networking-service "enp0s8" ...)
>
> to the list of services. No chance:
>
>    service "networking" provided more than once
>
> That must be because "lo" is already configured in %base-services. But 
> the documentation explicitly says that I can call 
> static-networking-service multiple times for multiple interfaces!

This works for me.  I have configured berlin.guixsd.org with two network
interfaces by simply providing static-networking-service twice.  I’m not
removing any services from %base-services:

  (services (cons* …
             (static-networking-service "enp6s4f0"
                                        "141.80.181.40"
                                        #:netmask "255.255.255.0"
                                        #:gateway "141.80.181.1")
             (static-networking-service "enp0s8"
                                        "192.168.0.1"
                                        #:netmask "255.255.255.0")
             …
             %base-services))

-- 
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net

Re: Adding a network interface

[Konrad Hinsen]

Hi Ricardo,

Thanks for your reply!

> This works for me.  I have configured berlin.guixsd.org with two network
> interfaces by simply providing static-networking-service twice.  I’m not
> removing any services from %base-services:
>
>   (services (cons* …
>              (static-networking-service "enp6s4f0"
>                                         "141.80.181.40"
>                                         #:netmask "255.255.255.0"
>                                         #:gateway "141.80.181.1")

OK, so my first try was right but my interpretation of the error message
wasn't. After some further exploration, the already-running network
service is indeed not the statically configured loopback, but
(dhcp-client-service), which handles all network adapters other than
loopback.

Configuring both of my adapters with static IPs works very well, but
is not practical for a laptop used in different networks. Back to
rethinking my deployment strategy...

Konrad.