Re: [meta-virtualization] Networking issue with l3s when using systemd

["Matt Spencer" <matt.spencer@arm.com>]

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Hey Bruce,

I understand that changing things can be difficult once launched.

But looking at the systemd documentation here https://wiki.archlinux.org/title/systemd-networkd and in the note that says 'Devices can also be matched by their type. E.g. Type=ether for Ethernet, Type=wlan for Wi-Fi and Type=wwan for WWAN. Note that Type=ether will also match virtual Ethernet interfaces (veth*), which may be undesirable.'

I have created a patch that modifies poky's meta/recipes-core/systemd/systemd-conf/wired.network to add '+Name=!veth*' to the Match clause which the team at Arm are reviewing with a view to upstream.

I feel that this should have been the default behaviour anyway?

/Matt
________________________________
From: meta-virtualization@lists.yoctoproject.org <meta-virtualization@lists.yoctoproject.org> on behalf of Bruce Ashfield via lists.yoctoproject.org <bruce.ashfield=gmail.com@lists.yoctoproject.org>
Sent: 14 June 2021 15:24
To: Matt Spencer <Matt.Spencer@arm.com>
Cc: meta-virtualization@lists.yoctoproject.org <meta-virtualization@lists.yoctoproject.org>
Subject: Re: [meta-virtualization] Networking issue with l3s when using systemd

On Mon, Jun 14, 2021 at 6:27 AM Matt Spencer <matt.spencer@arm.com> wrote:
>
> Hi all
>
> There seems to be a networking problem with k3s when using systemd.  The problem manifests in that none of the kube-system management containers are able to communicate with eachother.
>
> The root cause seems to be that systemd-networking is actively managing veth interfaces created by k3s/flannel.  This happens because of '/lib/systemd/network/80-wired.network' added by the systemd recipe, which is matching on Type=ether.
>
> My fix is to modify the 80-wired.network to add 'Name=eth*'.  With this in place, k3s works as expected.
>
> I am not sure what the correct upstream solution should be for Yocto?  Your help would be appreciated.
>

This particular issue is known, in the sense that we have run into it before.

At a minimum, I need to warn about it in the k3s README files.

I created the cni bbclass to manage potentially conflicting networking
configs on that front, but systemd-networking is yet another variable.

We don't want to globally make it conflict, since someone might have a
working networkd config that they want to use, and exactly how
networking is set up, tends to be more of a distro feature. So the
recipes need to tread carefully.

Which takes me back to the README, and an enhancement to the
cni-networking bbclass to be more generic and pick up / warn on
configuration issues like this.

bruce


> /Matt
>
>


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