[systemd-devel] systemd-networkd packet loss Ubuntu 18.04 (systemd 237)

[Luke Alexander]

Ah, no problem thanks for the info!

On Wed, Jul 8, 2020 at 12:17 PM Paul Menzel <
pmenzel+systemd-devel at molgen.mpg.de> wrote:

> Dear Luke,
>
>
> On 2020-07-08 13:10, Luke Alexander wrote:
>
> > I had a look through some of the issues against the systemd github repo
> but
> > could not find any matching - there were a couple which look promising
> but
> > don't completely resolve our issue.
> >
> > Our issue is that we have a k8s (1.18, kube-router CNI) cluster comprised
> > of a number of Ubuntu 16.04 nodes, we are in the process if upgrading the
> > nodes to Ubuntu 18.04 - however after upgrading the first node and adding
> > it back to the cluster we observed high packet loss from other cluster
> > nodes to the 18.04 node as well as ping error messages when running a
> > continuous ping from the 18.04 node to another node in the cluster, eg:
> >
> > 64 bytes from 10.8.11.1: icmp_seq=91 ttl=64 time=0.088 ms
> > 64 bytes from 10.8.11.1: icmp_seq=92 ttl=64 time=0.076 ms
> > ping: sendmsg: No buffer space available
> > ping: sendmsg: No buffer space available
> > ping: sendmsg: No buffer space available
> >
> > Another observation is that one of our daemonset pods (promtail) could
> not
> > start.
> >
> > systemctl --version
> > systemd 237
> > +PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP
> > +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN
> > -PCRE2 default-hierarchy=hybrid
> >
> > After many days of troubleshooting various possibilities, changing
> network
> > cable, NIC, a different server, various sysctl values, I eventually tried
> > switching from systemd-networkd to NetworkManager as the backend via
> > netplan config. After rebooting the server with NetworkManager in place
> and
> > re-adding the node back to the k8s cluster, the packet loss disappeared
> as
> > did the ping errors and the daemonset pod (promtail) also started
> normally.
> >
> > I would like to use Ubuntu's default of systemd-networkd to handle our
> > NIC/route config - but cannot until I've figured out what in
> > systemd-networkd is breaking.
> >
> > Any help is much appreciated on this matter.
>
> Unfortunately, upstream only supports the last two upstream versions of
> systemd. Please report the issue to the Ubuntu bug tracker Launchpad [1].
> It would probably help to verify, if the issue is still present in the
> newest
> version. So maybe try Ubuntu 20.04 first to see if it’s fixed there.
> Otherwise, building systemd yourself in Ubuntu should be doable too.
>
> I am sorry for the unsatisfying answer.
>
>
> Kind regards,
>
> Paul
>
>
> [1]: https://bugs.launchpad.net/ubuntu/+source/systemd
>
>
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