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networkd: prevent networkd interference of weave network devices #22

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cdemers
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@cdemers cdemers commented Jul 14, 2020

Prevent networkd interference of weave network devices

This change prevents systemd-networkd interference with
the Weave virtual interfaces weave, datapath and
vxlan-6784 are all created by Weave. Documentation on these
interfaces is available here:

This fixes DHCP issues introduced by networkd interference
reported by multiple users and mainly highlighted by this issue:

The issue doesn't seems to cause any significant impact on
performance, however it will cause Weave NPC to produce a
high volume of the following repetitive warning logs.

WARN: 2019/07/05 11:12:25.102451 UDP connection from 0.0.0.0:68 to 255.255.255.255:67 blocked by Weave NPC.

How to use

Having the weave.network file provided to networkd should
be enough.

Testing done

We have run many Flatcar instances in production with this configuration enabled, for at least one full week. The instances
are part of a many Kubernetes clusters using Weave as their network overlay.

@pothos
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pothos commented Jul 17, 2020

Hello,
thank you for providing a PR! It looks good but we first need to test it ourselves again.

@cdemers
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cdemers commented Jul 21, 2020

Thank you, we are still doing some more testing on our side (on AWS), we'll comment here if we find anything.

pothos added a commit that referenced this pull request Jul 27, 2020
networkd: prevent networkd interference of weave network devices by cdemers
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Ran tests on Digital Ocean and Azure

@pothos pothos merged commit 1ba0368 into flatcar:flatcar-master Jul 31, 2020
pothos added a commit to flatcar-archive/coreos-overlay that referenced this pull request Jul 31, 2020
The special weave devices are now excluded from networkd to prevent
interference.
This pulls in
flatcar/init#22
@pothos
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pothos commented Jul 31, 2020

Thank you for your contribution. This will be part of the next Alpha release.

pothos added a commit to flatcar-archive/coreos-overlay that referenced this pull request Sep 14, 2020
This pulls in the new sub key for flatcar-install
flatcar/init#25
and a networkd unit to exclude Weave interfaces from DHCP
flatcar/init#22
and an update to two other networkd units which lacked a match section
that is mandatory in future systemd versions
flatcar/init#23
jepio pushed a commit that referenced this pull request Feb 21, 2022
Enable iSCSI netroot devices on Flatcar
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2 participants