add simple static route support

[zabbal]

In addition to existing lxc.network.ipv4 and lxc.network.ipv4.gateway would be great to be able to specify static routes inside the container config:
lxc.network.ipv4.route = 192.168.1.4/10.2.3.9
which would add inside the container:
ip route add 192.168.1.4 via 10.2.3.9

Instead of / we could use word via or whatever syntax is more convenient to parse.

[blakedot]

Yes, it would be great if the value of this AVP could just be passed to the "ip route" command.

For IPv6 too :-)

Thanks very much.

[ghost]

+1
and yes - this would be awesome...

[stgraber]

you do realize that most Linux distributions will flush any route that's present at container boot time right?

[ghost]

Shouldn't it then flush 'away' the default gw as well - set via 'lxc.network.ipv4.gateway'?
[that's why I too think that it may be possible]

[stgraber]

Yeah, it would. If your distro doesn't flush a pre-configured IP or default gateway, then this feature would work.

[ar45]

Which distros do flush away lxc.network.ipv4.gateway?

[stgraber]

ifupdown on Debian/Ubuntu used to either flush the routing table at boot or just completely fail when then attempting to add routing entries which are already present (causing boot to hang).

[ar45]

I wonder. I am using that with debian jessie host and jessie containers and it works for me well. Is there any specific setup that is causing it?

[stgraber]

Could be that ifupdown isn't flushing routes anymore (pretty sure NetworkManager still does), so the only problem you'd run into is if you had a conflicting route being applied with ifupdown.

[brauner]

That's not a feature we're likely to introduce for the aforementioned reasons by @stgraber.

[apardyl]

I'm quite sure that the at least in case of debian, ubuntu, fedora and archlinux (installed with the download template) the guest os does not override network settings unless it receives a valid DHCP response.

A setting like lxc.net.[n].ipv[4/6].route = address/mask via gateway would be extremely useful in environments, where manual static configuration is required - it would enable users to set the entire networking configuration in the container config (as currently possible when only specifying the default gateway is sufficient).

Also @stgraber I thought that the entire point of lxc.net.[n].ipv[4/6].* options is to have all network config done by lxc, without touching it from the inside of the container (a very useful feature when creating containers from a template) - if you use ifupdown/NetworkManager/other you do not set lxc.net.[n].ipv[4/6].address and lxc.net.[n].ipv[4/6].gateway either because as you mentioned it would get flushed.

Sorry for commenting on such an old thread, but I was just going to ask you whether it would be possible to implement this when I found this issue, so I decided to comment here instead of opening a new one.

[kawogi]

Assuming this will not get implemented: what's the recommended way to add static routes to interfaces that are otherwise completely declared in the container's config?
I'm either used to configure them entirely within the container or externally. I haven't found mixed examples so far (Debian in my case).

[apardyl]

@fyl2xp1 currently I'm doing it like this:

# setup static routing
lxc.hook.mount = /etc/lxc/setup_routing.sh

where /etc/lxc/setup_routing.sh (file on lxc host) is:

ip ro add 10.30.0.0/16 via 10.20.0.1
ip ro add 10.10.0.0/16 via 10.20.0.1

It's a bit hacky, but it works.

[kawogi]

Thanks, I added to my /etc/network/interfaces:

auto eth3
iface eth3 inet manual
    post-up route add -net ...
    pre-down route del -net ...

This seems to work reliably but still feels odd because all other adapters as missing from that list and the rest of the interface's configuration resides in an external configuration.

[dominikdev-m]

Anything new on this?