[Bug 2028023] [NEW] [jammy] DNS issue triggered by command "udevadm trigger --subsystem-nomatch=input"

[Aristo Chen]

Public bug reported:

[Summary]
In jammy server image, when we use NetworkManager as netplan renderer, we may have DNS issue after executing command "udevadm trigger --subsystem-nomatch=input" as super user, the udevadm command may also be executed when we use "apt install XXXXXX" or "snap install XXXXXX".

[Steps to reproduce]
1. Login to a jammy server(jammy desktop environment works fine) image environment with Vagrant
2. execute command "apt install network-manager"
3. modify netplan config to use NetworkManager as renderer
"""
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager
"""
4. reboot
5. execute command "ping google.com" first to make sure DNS works fine
6. execute command "udevadm trigger --subsystem-nomatch=input" as super user
7. execute command "ping google.com" to check if DNS still works fine
8. if DNS works fine, then repeat step 6-7, the fail rate is around 20-30%

[Other info]
I have tested the above mentioned steps for the following scenarios, which work fine without DNS issue
1. Using focal server environment with Vagrant, there is no DNS issue
2. Using jammy server environment with Vagrant which has DNS issue, then add the kinetic/kinetic-updates source list, install systemd(version: 251.4-1ubuntu7.3) from kinetic, and there is no DNS issue

If using focal server environment with Vagrant, then add the
jammy/jammy-updates source list, install systemd(version:
249.11-0ubuntu3.9) from jammy, then I will have DNS issue as well by
following the steps mentioned in [Steps to reproduce]

[Other info - Vagrantfile]
The following content is for the Vagrantfile that I used to test
"""
Vagrant.configure("2") do |config|
  if Vagrant.has_plugin?("vagrant-timezone")
    config.timezone.value = :host
  end
  config.vm.define "test" do |test|
    test.vm.box = "ubuntu/jammy64"
    test.vm.provider "virtualbox" do |vb|
      vb.name = "test2"
      vb.memory = "4096"
      vb.cpus = 4
      config.disksize.size = "50GB"
    end
  end
end
"""

[Fail rate]
20-30%

[Test script]
The following is the script that I used to test. Ideally it should run forever
"""
#!/bin/bash

set -ex

counter=1

while true; do
 echo "$(date): test round ${counter}"
 counter=$((counter + 1))
 sudo udevadm trigger --subsystem-nomatch=input
 ping google.com -c 2
 sleep 0.5
done
"""

** Affects: oem-priority
     Importance: Critical
     Assignee: Aristo Chen (aristochen)
         Status: New

** Affects: systemd (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: oem-priority

** Also affects: oem-priority
   Importance: Undecided
       Status: New

** Changed in: oem-priority
   Importance: Undecided => Critical

** Changed in: oem-priority
     Assignee: (unassigned) => Aristo Chen (aristochen)

-- 
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https://bugs.launchpad.net/bugs/2028023

Title:
  [jammy] DNS issue triggered by command "udevadm trigger --subsystem-
  nomatch=input"

Status in OEM Priority Project:
  New
Status in systemd package in Ubuntu:
  New

Bug description:
  [Summary]
  In jammy server image, when we use NetworkManager as netplan renderer, we may have DNS issue after executing command "udevadm trigger --subsystem-nomatch=input" as super user, the udevadm command may also be executed when we use "apt install XXXXXX" or "snap install XXXXXX".

  [Steps to reproduce]
  1. Login to a jammy server(jammy desktop environment works fine) image environment with Vagrant
  2. execute command "apt install network-manager"
  3. modify netplan config to use NetworkManager as renderer
  """
  # Let NetworkManager manage all devices on this system
  network:
    version: 2
    renderer: NetworkManager
  """
  4. reboot
  5. execute command "ping google.com" first to make sure DNS works fine
  6. execute command "udevadm trigger --subsystem-nomatch=input" as super user
  7. execute command "ping google.com" to check if DNS still works fine
  8. if DNS works fine, then repeat step 6-7, the fail rate is around 20-30%

  [Other info]
  I have tested the above mentioned steps for the following scenarios, which work fine without DNS issue
  1. Using focal server environment with Vagrant, there is no DNS issue
  2. Using jammy server environment with Vagrant which has DNS issue, then add the kinetic/kinetic-updates source list, install systemd(version: 251.4-1ubuntu7.3) from kinetic, and there is no DNS issue

  If using focal server environment with Vagrant, then add the
  jammy/jammy-updates source list, install systemd(version:
  249.11-0ubuntu3.9) from jammy, then I will have DNS issue as well by
  following the steps mentioned in [Steps to reproduce]

  [Other info - Vagrantfile]
  The following content is for the Vagrantfile that I used to test
  """
  Vagrant.configure("2") do |config|
    if Vagrant.has_plugin?("vagrant-timezone")
      config.timezone.value = :host
    end
    config.vm.define "test" do |test|
      test.vm.box = "ubuntu/jammy64"
      test.vm.provider "virtualbox" do |vb|
        vb.name = "test2"
        vb.memory = "4096"
        vb.cpus = 4
        config.disksize.size = "50GB"
      end
    end
  end
  """

  [Fail rate]
  20-30%

  [Test script]
  The following is the script that I used to test. Ideally it should run forever
  """
  #!/bin/bash

  set -ex

  counter=1

  while true; do
   echo "$(date): test round ${counter}"
   counter=$((counter + 1))
   sudo udevadm trigger --subsystem-nomatch=input
   ping google.com -c 2
   sleep 0.5
  done
  """

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