[systemd-devel] Can't connect to WiFi when the wired and the wireless interfaces are bonded

[Doron Behar]

I've bonded my wireless and wired network interfaces with
systemd-networkd using an active-backup mode.

These are the configuration files I have:

/etc/systemd/network/10-bond0.netdev

	[NetDev]
	Name=bond0
	Kind=bond

	[Bond]
	Mode=active-backup
	
----

/etc/systemd/network/20-wired.network
	[Match]
	Name=enp0s25
	
	[Network]
	Bond=bond0

----

/etc/systemd/network/25-wireless.network

	[Match]
	Name=wlp2s0
	
	[Network]
	Bond=bond0

----

/etc/systemd/network/35-tethering.network

	[Match]
	Name=enp0s20u*
	
	[Network]
	Bond=bond0

----

/etc/systemd/network/40-bond0.network

	[Match]
	Name=bond0
	
	[Network]
	DHCP=yes

----

I've noticed that if I boot without any internet connection, WiFi or
Ethernet, and I connect to a WiFi network (only after the boot),
`wpa_supplicant` reports I'm connected to the WiFi network but I'm not
connected to the internet.

Here is the output of `networkctl status`:

●        State: degraded
       Address: fe80::a05d:c4ff:feca:efaa on bond0

And `networkctl list`:

	IDX LINK             TYPE               OPERATIONAL SETUP     
	  1 lo               loopback           carrier     unmanaged 
	  2 bond0            bond               degraded    configuring
	  3 enp0s25          ether              no-carrier  configuring
	  4 wlp2s0           wlan               carrier     configuring
	
	4 links listed.

And the output of `ip addr`:

	1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
	    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
	    inet 127.0.0.1/8 scope host lo
	       valid_lft forever preferred_lft forever
	    inet6 ::1/128 scope host 
	       valid_lft forever preferred_lft forever
	2: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
	    link/ether a2:5d:c4:ca:ef:aa brd ff:ff:ff:ff:ff:ff
	    inet6 fe80::a05d:c4ff:feca:efaa/64 scope link 
	       valid_lft forever preferred_lft forever
	3: enp0s25: <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc fq_codel master bond0 state DOWN group default qlen 1000
	    link/ether a2:5d:c4:ca:ef:aa brd ff:ff:ff:ff:ff:ff
	4: wlp2s0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP group default qlen 1000
	    link/ether a2:5d:c4:ca:ef:aa brd ff:ff:ff:ff:ff:ff

Is this how it is supposed to behave? Is `systemd-networkd` supposed to be
used only for servers without roaming internet connections that change
after boot?