Setting DuplicateAddressDetection=none doesn't disable DAD for link-local IPs
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| systemd |
Fix Released
|
Unknown
|
|||
| systemd (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
| Jammy |
Fix Released
|
Undecided
|
Unassigned | ||
| Kinetic |
Fix Released
|
Medium
|
Unassigned | ||
Bug Description
[impact]
manual disabling of ipv4 DAD (IACD) for static link-local address does not work in jammy
[test case]
see 'Reproducer' in original description below
[regression potential]
failure to disable DAD, or incorrect disabling of DAD, or networkd issues around parsing of DAD config parsing
[scope]
this is needed for j and k
introduced upstream by commit 1cf4ed142d6c1e2
fixed upstream by commit 2859932bd64d61a
[original description]
A customer reported network disconnections on their storage
servers when running 'netplan apply'. The culprit was that
they have link-local addresses configured and the Duplicate
Address Detection (DAD) mechanism was delaying the interfaces
from coming back up.
As a workaround we tried to disable DAD for the interfaces
but that's not working in Ubuntu 22.04:
I've noticed that setting DuplicateAddres
interface with a link-local address (e.g., 169.254.*) via a
.network file added to /etc/systemd/
disable Duplicate Address Detection.
OS and package versions:
-------
- Description: Ubuntu Jammy Jellyfish (development branch). Release: 22.04
- systemd 249.5-2ubuntu4
Reproducer:
-----------
1- Set up Ubuntu 22.04 VM
2- Increase systemlog level:
mkdir -p /etc/systemd/
cat > /etc/systemd/
[Service]
Environment=
EOF
systemctl daemon-reload && systemctl restart systemd-networkd
3- Configure a link-local address to a network interface on the VM:
vi /etc/systemd/
# add
[Match]
Name=enp7s0
[Address]
Address=
DuplicateAddres
4- Restart services and apply
systemctl daemon-reload && systemctl restart systemd-networkd && systemctl restart networkd-
netplan apply
5- Check if DAD is running (it should):
journalctl -b -u systemd-networkd --no-pager -o short-precise | grep -i ACD
6- Set DuplicateAddres
/etc/systemd/
7- Restart services and apply as in step 4
8- Check if DAD is running as in step 5 (it shouldn't, but
it's there)
After step 7 DAD should be disabled as expected and it
shouldn't be executed when running 'netplan apply' but
it is actually executed.
I think this commit [1] may be related (landed in systemd
v249). I've also tested the out-of-the-box systemd versions
for Focal and Impish but there I can effectively disable
DAD. If the IPs are set to non-link local addresses then
the problem is not observed anymore.
[1] https:/
| Alejandro Santoyo Gonzalez (al3jandrosg) wrote | #1 |
| summary: |
- Setting DuplicateAddressDetection=none doesn't do anything + Setting DuplicateAddressDetection=none doesn't disable DAD |
| summary: |
- Setting DuplicateAddressDetection=none doesn't disable DAD + Setting DuplicateAddressDetection=none doesn't disable DAD for link- + local IPs |
| Dan Streetman (ddstreet) wrote | #2 |
| Alejandro Santoyo Gonzalez (al3jandrosg) wrote | #3 |
| Launchpad Janitor (janitor) wrote | #4 |
| Changed in systemd (Ubuntu): | |
| status: | New → Confirmed |
| Lukas Märdian (slyon) wrote | #5 |
| Changed in systemd (Ubuntu): | |
| status: | Confirmed → Triaged |
| importance: | Undecided → Medium |
| Lukas Märdian (slyon) wrote | #6 |
| Changed in systemd: | |
| status: | Unknown → New |
| Changed in systemd: | |
| status: | New → Fix Released |
| description: | updated |
| Lukas Märdian (slyon) wrote | #7 |
| Changed in systemd (Ubuntu Kinetic): | |
| status: | Triaged → Fix Committed |
| Changed in systemd (Ubuntu Jammy): | |
| status: | New → In Progress |
| Launchpad Janitor (janitor) wrote | #8 |
| Changed in systemd (Ubuntu Kinetic): | |
| status: | Fix Committed → Fix Released |
| Steve Langasek (vorlon) wrote Please test proposed package | #9 |
| Changed in systemd (Ubuntu Jammy): | |
| status: | In Progress → Fix Committed |
| tags: | added: verification-needed verification-needed-jammy |
| Alejandro Santoyo Gonzalez (al3jandrosg) wrote | #10 |
| Dan Streetman (ddstreet) wrote | #11 |
| tags: |
added: verification-done verification-done-jammy removed: verification-needed verification-needed-jammy |
| Launchpad Janitor (janitor) wrote | #12 |
| Changed in systemd (Ubuntu Jammy): | |
| status: | Fix Committed → Fix Released |
| Robie Basak (racb) wrote Update Released | #13 |
> I think this commit [1] may be related (landed in systemd v249)
yeah, that commit seems to be intentionally forcing ACD on for statically configured ipv4, i'm not sure quite why, it seems like a user-configured setting should be honored; but possibly Yu was trying to default it to on instead of overriding user config.