cloud-init-dev team mailing list archive

[Ryan Harper <ryan.harper@xxxxxxxxxxxxx>]

The proposal to merge ~raharper/cloud-init:fix/lp-1766287-run-after-udev-settle-service into cloud-init:master has been updated.

Commit message changed to:

cloud-init-local: use systemd-udev-settle.service for stable nic names
    
The cloud-init-local.service expects that any network device name
changes have already been completed by the kernel or udev daemon.
While at least in Ubuntu the systemd-udev-settle.service is enabled,
nothing in the Ubuntu cloud images by default has a Wants for this
service so it does not run.

In some situations we've found that the renaming of interfaces from
kernel names (eth0, eth1, etc) to their persistent names (eno1, ens3,
enp0s1, etc) may happen after cloud-init-local has started where it
reads values from sysfs about what network devices are present, and
which device to use as a fallback nic.

Subsequently, cloud-init-local would write out network configuration
for a kernel device name which would no longer be present by the time
that networking services start to bring up the devices.  The result is
that the instance does not get networking configured.  Prior to use of
systemd-networkd, the Ubuntu 'networking.service' unit included a call
to udevadm settle which is why this race is not seen on a Xenial
system.

LP: #1766287

For more details, see:
https://code.launchpad.net/~raharper/cloud-init/+git/cloud-init/+merge/344198
-- 
Your team cloud-init commiters is requested to review the proposed merge of ~raharper/cloud-init:fix/lp-1766287-run-after-udev-settle-service into cloud-init:master.