[Bug 1951653] [NEW] can't use NM for ethernet device on 20.04 LTS because it is 'strictly unmanaged'

[Steve Langasek]

Public bug reported:

I have tried to tell netplan to let my ethernet device be managed by
NetworkManager, so that I can then configure a pppoe connection on top
of this device.

This fails with:

# nmcli c up netplan-wan
Error: Connection activation failed: No suitable device found for this connection (device lo not available because device is strictly unmanaged).
#

I don't know why it mentions 'lo' in that message, but the wan interface
is unmanaged (as are all devices on the system, but this one is supposed
to be managed):

# nmcli d status | grep wan
wan       ethernet  unmanaged  --         
#

After much searching, I've figured out that this comes from
/usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf:

keyfile]
unmanaged-devices=*,except:type:wifi,except:type:gsm,except:type:cdma

Even though I've told netplan to use the NM renderer for this device,
the configuration emitted by netplan is insufficient to override this.

Using the workaround from https://askubuntu.com/questions/71159/network-
manager-says-device-not-managed (sudo touch
/etc/NetworkManager/conf.d/10-globally-managed-devices.conf) doesn't
work, but if I set NetworkManager as the toplevel renderer in
/etc/netplan, /run/NetworkManager/conf.d/10-globally-managed-
devices.conf is emitted, which evidently DOES work.  But I only have one
device that I want rendered by NM, so I shouldn't have to declare NM at
the top level of the yaml with a lot of duplication in order to get this
result.

I would argue that the 10-globally-managed-devices.conf should not be
there at all.  But if it is going to be, then netplan needs to
consistently override it whenever there is any use of the NetworkManager
backend.

** Affects: netplan.io (Ubuntu)
     Importance: High
         Status: New

** Affects: network-manager (Ubuntu)
     Importance: High
         Status: New

** Also affects: netplan.io (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: netplan.io (Ubuntu)
   Importance: Undecided => High

** Changed in: network-manager (Ubuntu)
   Importance: Undecided => High

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https://bugs.launchpad.net/bugs/1951653

Title:
  can't use NM for ethernet device on 20.04 LTS because it is 'strictly
  unmanaged'

Status in netplan.io package in Ubuntu:
  New
Status in network-manager package in Ubuntu:
  New

Bug description:
  I have tried to tell netplan to let my ethernet device be managed by
  NetworkManager, so that I can then configure a pppoe connection on top
  of this device.

  This fails with:

  # nmcli c up netplan-wan
  Error: Connection activation failed: No suitable device found for this connection (device lo not available because device is strictly unmanaged).
  #

  I don't know why it mentions 'lo' in that message, but the wan
  interface is unmanaged (as are all devices on the system, but this one
  is supposed to be managed):

  # nmcli d status | grep wan
  wan       ethernet  unmanaged  --         
  #

  After much searching, I've figured out that this comes from
  /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf:

  keyfile]
  unmanaged-devices=*,except:type:wifi,except:type:gsm,except:type:cdma

  Even though I've told netplan to use the NM renderer for this device,
  the configuration emitted by netplan is insufficient to override this.

  Using the workaround from
  https://askubuntu.com/questions/71159/network-manager-says-device-not-
  managed (sudo touch /etc/NetworkManager/conf.d/10-globally-managed-
  devices.conf) doesn't work, but if I set NetworkManager as the
  toplevel renderer in /etc/netplan,
  /run/NetworkManager/conf.d/10-globally-managed-devices.conf is
  emitted, which evidently DOES work.  But I only have one device that I
  want rendered by NM, so I shouldn't have to declare NM at the top
  level of the yaml with a lot of duplication in order to get this
  result.

  I would argue that the 10-globally-managed-devices.conf should not be
  there at all.  But if it is going to be, then netplan needs to
  consistently override it whenever there is any use of the
  NetworkManager backend.

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