[Bug 1967084] Re: netplan dbus returns "false" in io.netplan.Netplan.Config.Set with networkd

[Lukas Märdian]

Fixed in v0.105 & backported to Focal.

** Changed in: netplan
       Status: Fix Committed => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to netplan.io in Ubuntu.
Matching subscriptions: foundations-bugs
https://bugs.launchpad.net/bugs/1967084

Title:
  netplan dbus returns "false" in io.netplan.Netplan.Config.Set with
  networkd

Status in netplan:
  Fix Released
Status in netplan.io package in Ubuntu:
  Fix Released
Status in netplan.io source package in Focal:
  Fix Released

Bug description:
  [Impact] 
  * netplan-dbus can time-out and return FALSE after 5 sec (irrespective of the given timeout parameter) on calling the io.netplan.Netplan.Config.Try DBus method
  * This happens if a network device is set up, which never finishes configuring in systemd-networkd (e.g. an empty bridge, using DHCP).

  [Test Plan]
  $ cat ./repro.sh
  set -ev
  P=$(dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan /io/netplan/Netplan io.netplan.Netplan.Config | grep "object path" | cut -d'"' -f2)
  echo $P
  dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan $P io.netplan.Netplan.Config.Set string:bridges.br54.dhcp4=true string:90-foo
  dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan $P io.netplan.Netplan.Config.Try uint32:300

  $ chmod +x repro.sh
  $ time ./repro.sh
  P=$(dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan /io/netplan/Netplan io.netplan.Netplan.Config | grep "object path" | cut -d'"' -f2)
  echo $P
  /io/netplan/Netplan/config/K0PEL1
  dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan $P io.netplan.Netplan.Config.Set string:bridges.br54.dhcp4=true string:90-foo
  method return time=1651225120.656093 sender=:1.48 -> destination=:1.49 serial=6 reply_serial=2
     boolean true
  dbus-send --type=method_call --system --print-reply --dest=io.netplan.Netplan $P io.netplan.Netplan.Config.Try uint32:300
  method return time=1651225126.820211 sender=:1.48 -> destination=:1.50 serial=8 reply_serial=2
     boolean true

  real    0m6.352s
  user    0m0.019s
  sys     0m0.020s

  => Make sure the final io.netplan.Netplan.Config.Try() method call
  returns TRUE.

  [Where problems could occur]
  This change touches netplan's dbus daemon (netplan-dbus), so if anything goes wrong problems could occur interacting with the io.netplan.Netplan DBus interface, but should not affect the netplan generator at a system level.

  [Other Info]
  * The issue has already been fixed for Core20 in netplan.io 0.104-0ubuntu2~20.04.1+core1 via https://launchpad.net/~canonical-foundations/+archive/ubuntu/ubuntu-image – So no need to rush this as an SRU for Focal
  * The fix is already staged for Focal SRU at: https://git.launchpad.net/~ubuntu-core-dev/netplan/+git/ubuntu/commit/?h=ubuntu/focal&id=0fa3404c9627d69adf647db9911cf36cdf9b90b2

  
  === Original description ===

  As part of our snapd core integration testing we run the spread test
  for netplan on a UC20 PI device.

  On this device our test fails with:
  """
  2022-03-25 14:33:00 Error executing external:ubuntu-core-20-arm-32:tests/core/netplan-cfg (external:ubuntu-core-20-arm-32) :
  -----
  + echo 'Getting version works'
  Getting version works
  + snap get system system.network.netplan.network.version
  + MATCH '^2$'
  + echo 'Getting the full document works and it is valid json'
  Getting the full document works and it is valid json
  + jq .
  + snap get -d system system.network.netplan
  {
    "system.network.netplan": {
      "network": {
        "ethernets": {
          "eth0": {
            "dhcp4": true,
            "match": {
              "macaddress": "b8:27:eb:41:42:43"
            },
            "set-name": "eth0"
          }
        },
        "version": 2
      }
    }
  }
  + echo 'Check that setting adding a br54 interface via netplan works'
  Check that setting adding a br54 interface via netplan works
  + snap set system system.network.netplan.network.bridges.br54.dhcp4=true
  error: cannot perform the following tasks:
  - Run configure hook of "core" snap (run hook "configure": cannot try netplan config: no specific reason returned from netplan)
  -----
  """

  This error means that snapd called io.netplan.Netplan.Config.Set and
  got a "false" without an error from that call (c.f.
  https://github.com/snapcore/snapd/blob/master/overlord/configstate/configcore/netplan.go#L218)

  [edit: now this also fails in GCE testing on amd64 and this looks like
  a regression as this used to work].

To manage notifications about this bug go to:
https://bugs.launchpad.net/netplan/+bug/1967084/+subscriptions