[Bug 1872589] [NEW] systemd-networkd is not honoring UseRoutes=false

[Rafael David Tinoco]

Public bug reported:

When netplan configures dhcp4-overrides and set "use-routes" to false,
systemd-networkd should be configured with UseRoutes=false. It is.
Unfortunately looks like systemd-networkd is not honoring it and
configuring the default gateways for the interfaces no matter what.

Ubuntu Focal: systemd: 245.4-2ubuntu1

----

$ sudo cat /etc/netplan/50-cloud-init.yaml
network:
    ethernets:
        enp5s0:
            match:
                macaddress: 00:16:3e:af:c4:d6
            set-name: eth0
            dhcp4: true
            dhcp-identifier: mac
        enp6s0:
            match:
                macaddress: 00:16:3e:50:11:9c
            set-name: iscsi01
            dhcp4: true
            dhcp-identifier: mac
            dhcp4-overrides:
              use-routes: false
        enp7s0:
            match:
                macaddress: 00:16:3e:b3:cc:50
            set-name: iscsi02
            dhcp4: true
            dhcp-identifier: mac
            dhcp4-overrides:
              use-routes: false
    version: 2
    renderer: networkd

----

$ cat /var/run/systemd/network/10-netplan-enp6s0.network

[Match]
MACAddress=00:16:3e:50:11:9c
Name=iscsi01

[Network]
DHCP=ipv4
LinkLocalAddressing=ipv6

[DHCP]
ClientIdentifier=mac
RouteMetric=100
UseMTU=true
UseRoutes=false

--

$ ip route show | grep default
default via 10.250.93.1 dev iscsi02 proto dhcp src 10.250.93.101 metric 100
default via 10.250.94.1 dev iscsi01 proto dhcp src 10.250.94.167 metric 100
default via 10.250.97.1 dev eth0 proto dhcp src 10.250.97.123 metric 100

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

** Changed in: systemd (Ubuntu)
       Status: New => Confirmed

** Changed in: systemd (Ubuntu)
       Status: Confirmed => Triaged

** Description changed:

+ When netplan configures dhcp4-overrides and set "use-routes" to false,
+ systemd-networkd should be configured with UseRoutes=false. It is.
+ Unfortunately looks like systemd-networkd is not honoring it and
+ configuring the default gateways for the interfaces no matter what.
  
- When netplan configures dhcp4-overrides and set "use-routes" to false, systemd-networkd should be configured with UseRoutes=false. It is. Unfortunately looks like systemd-networkd is not honoring it and configuring the default gateways for the interfaces no matter what.
+ Ubuntu Focal: systemd: 245.4-2ubuntu1
  
  ----
  
  $ sudo cat /etc/netplan/50-cloud-init.yaml
  network:
-     ethernets:
-         enp5s0:
-             match:
-                 macaddress: 00:16:3e:af:c4:d6
-             set-name: eth0
-             dhcp4: true
-             dhcp-identifier: mac
-         enp6s0:
-             match:
-                 macaddress: 00:16:3e:50:11:9c
-             set-name: iscsi01
-             dhcp4: true
-             dhcp-identifier: mac
-             dhcp4-overrides:
-               use-routes: false
-         enp7s0:
-             match:
-                 macaddress: 00:16:3e:b3:cc:50
-             set-name: iscsi02
-             dhcp4: true
-             dhcp-identifier: mac
-             dhcp4-overrides:
-               use-routes: false
-     version: 2
-     renderer: networkd
+     ethernets:
+         enp5s0:
+             match:
+                 macaddress: 00:16:3e:af:c4:d6
+             set-name: eth0
+             dhcp4: true
+             dhcp-identifier: mac
+         enp6s0:
+             match:
+                 macaddress: 00:16:3e:50:11:9c
+             set-name: iscsi01
+             dhcp4: true
+             dhcp-identifier: mac
+             dhcp4-overrides:
+               use-routes: false
+         enp7s0:
+             match:
+                 macaddress: 00:16:3e:b3:cc:50
+             set-name: iscsi02
+             dhcp4: true
+             dhcp-identifier: mac
+             dhcp4-overrides:
+               use-routes: false
+     version: 2
+     renderer: networkd
  
  ----
  
  $ cat /var/run/systemd/network/10-netplan-enp6s0.network
  
  [Match]
  MACAddress=00:16:3e:50:11:9c
  Name=iscsi01
  
  [Network]
  DHCP=ipv4
  LinkLocalAddressing=ipv6
  
  [DHCP]
  ClientIdentifier=mac
  RouteMetric=100
  UseMTU=true
  UseRoutes=false
  
  --
  
  $ ip route show | grep default
  default via 10.250.93.1 dev iscsi02 proto dhcp src 10.250.93.101 metric 100
  default via 10.250.94.1 dev iscsi01 proto dhcp src 10.250.94.167 metric 100
  default via 10.250.97.1 dev eth0 proto dhcp src 10.250.97.123 metric 100

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https://bugs.launchpad.net/bugs/1872589

Title:
  systemd-networkd is not honoring UseRoutes=false

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