netplan apply triggers udev add events for every network interface

[Alberto Contreras]

netplan.io version 1.0-3ubuntu1, on Ubuntu 24.10, triggers udev add events for every already present network interface:

```
$ lxc launch ubuntu-daily:o oo

# open `udevadm monitor` on another window within the container

o: # netplan apply

o: # udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[23616.687850] add /devices/virtual/net/eth0 (net)
KERNEL[23616.687890] add /devices/virtual/net/lo (net)
UDEV [23616.691806] add /devices/virtual/net/lo (net)
UDEV [23616.697810] add /devices/virtual/net/eth0 (net)
```

This is wrong by its own, but, with cloud-init on aws images is even worse because:

cloud-init installs the following udev rules to configure hotplugged nics:

```
# cat /etc/udev/rules.d/90-cloud-init-hook-hotplug.rules
# Installed by cloud-init due to network hotplug userdata
ACTION!="add|remove", GOTO="cloudinit_end"

ENV{ID_NET_DRIVER}=="vif|ena|ixgbevf", GOTO="cloudinit_hook"
GOTO="cloudinit_end"

LABEL="cloudinit_hook"
SUBSYSTEM=="net", RUN+="/usr/lib/cloud-init/hook-hotplug"
LABEL="cloudinit_end"

```

which gets triggered by the udev add events, and hook-hotplug instructs cloud-init to configure the new nic, and during that reconfiguration `netplan apply` is called by cloud-init, which starts an infinite loop.

[Alberto Contreras (aciba)]

cloud-init logs on aws

[Alberto Contreras (aciba)]

Marking cloud-init as invalid, as the problem is not caused by it directly.

[Lukas Märdian (slyon)]

Might be related to https://github.com/canonical/netplan/pull/479 (parts of it landed in the oracular package already)

[Lukas Märdian (slyon)]

systemd-udevd does not apply ethtool changes, that are defined in a .link file, on a CHANGE uevent anymore, as of systemd v265.

It still seems to apply those changes for ADD, BIND & MOVE udev actions, though. Going with a MOVE action seems more senstible here, as that should cover all the cases Netplan needs and avoid triggering the above mentioned cloud-init rule, running on ADD uevents.

[Launchpad Janitor (janitor)]

This bug was fixed in the package netplan.io - 1.0.1-1ubuntu1

---------------
netplan.io (1.0.1-1ubuntu1) oracular; urgency=medium

  * Merge from Debian unstable. Remaining changes:
    - d/p/0003-Revert-wait-online-disabled-wait-online-for-stable-1.patch:
      Fix wait-online via s-n-wait-online.service.d/10-netplan.
    - d/libnetplan1.symbols: Update for new (private) symbol

netplan.io (1.0.1-1) unstable; urgency=medium

  * New upstream release: 1.0.1:
    - sriov: accept setting the eswitch mode without VFs (LP: #2020409)
    - cli/sriov: refactoring
    - tests: use proper 0o600 file permissions in more places
    - doc: Adding missing 'watchfiles' dependency for Sphinx
    - doc: Minor fixes in lang. and mark-up in YAML reference
    - doc: Tutorial reorg & lang. + formatting improvements
    - networkd: add wait-online enumeration utils
    - generate: enable systemd-networkd-wait-online for non-optional interfaces
    - CLI:utils: Do not ask for daemon-reload password interactively
    - CLI:generate: call daemon-reload after (re-)generating services
    - wait-online: Do not block on loopback interface
    - generate: Do not touch wait-online, if we don't have any networkd NetDefs
    - wait-online: wait for existing interfaces only and downgrade operational
      state for interfaces without IP configuration
    - wait-online: account for DHCPv4/v6 addresses
    - wait-online: do not require virtual devices to be created already
    - wait-online: recognize that bridge/bond members will never gain
      link-local addresses
    - networkd:apply: Drop handling of legacy wpa@ instance units
    - wait-online: disabled wait-online for stable 1.0
    - test:integration: Try to improve test flakyness
    - autopkgtest: More fixes for flaky 'ethernets' test
    - Increase some test timeouts to account for slow (riscv64) buildds
    SECURITY UPDATE:
    - libnetplan: use more restrictive file permissions
      (Closes: #1072789, LP: #2065738, LP: #1987842)
    - CVE-2022-4968
    - libnetplan: escape control characters
    - backends: escape file paths
    - backends: escape semicolons in service units (LP: #2066258)
    Bug fixes:
    - cli: Fix logging setup when python-rich is not present
    - CI: fix DebCI case for no-change rebuilds
    - CI: adopt autopkgtest for 1.0-1 on 22.04
    - doc: Update README, move CODE_OF_CONDUCT
    - doc: fix en_GB spelling
    - CI: adopt snapd.patch for autopkgtest SRU (LP: #2051939)
    - parse-nm: add a workaround for the DoT DNS option (LP: #2055148)
    - CI: Install netplan-ci PPA
    - parse: don't remove datalist items during iteration
    - ATTN: parse/bonds: handle same primary in multiple bonds
    - parse/bonds: don't fail on primary reassignment
    - cli/sriov: set eswitch regardless of pcidev.vfs
    - doc: Fix wrong bonds.parameters.mode syntax in example
    - parse: fix redefinition of gateway(4|6)
    - doc:tutorial: fix whitespace formatting
    - util: fix potential NULL pointer assert
    - python: elements of __all__ must be strings
    - tests: fix diff test with iproute2 6.8
    - cli/generate: skip daemon_reload with --mapping
    - test: cleanup after wait_online tes...

[Alberto Contreras (aciba)]

Thanks for the work here. I can confirm that netplan.io 1.0.1-1ubuntu1 triggers the following udev events while `netplan apply` which fixes the issue:

KERNEL[318.736089] move /devices/pci0000:00/0000:00:05.0/net/ens5 (net)
KERNEL[318.736131] move /devices/virtual/net/lo (net)
UDEV [318.738939] move /devices/virtual/net/lo (net)
UDEV [318.740502] move /devices/pci0000:00/0000:00:05.0/net/ens5 (net)