Description of problem:

We have a server with 2000 vlan interfaces. When we manualy start the systemd-networkd service, everything works fine.
But, at boot, the same service randomly configure only aroud 1400 interfaces. The others stay in pending state for ever (as shown with networkctl). Restarting systemd-networkd fix this.


Version-Release number of selected component (if applicable):

systemd-networkd-219-19.el7_2.13.x86_64

How reproducible:

static

Steps to Reproduce:
1. Have an ethernet interface, let say ens6
2. Configure /etc/systemd/network/ens6.network with
[Match]
Name=ens6

[Network]
VLAN=vlan1
VLAN=vlan2
...
VLAN=vlan2000

3. Configure each /etc/systemd/network/vlanX.netdev with
[NetDev]
Name=vlanX
Kind=vlan
 
[VLAN]
Id=X

4. Configure each /etc/systemd/network/vlanX.network with
[Match]
Name=vlanX

[Address]
Address=172.A.B.C/32

5. systemctl retart systemd-networkd brings the 2000 interfaces and their IP

6. reboot and do ip a|grep "172\.16"|wc -l (aroud 1400). All vlan interfaces are up, but not all the IP are set. Command networkctl shows interfaces in pending state. Nothing happens next.

7. systemctl restart systemd-networkd fix the problem after boot.


Actual results:
systemctl restart systemd-networkd works
Same service at boot, doesn't works for all the interfaces


Expected results:
should work the same. No interface in pending state for ever.


Additional info:
works (kind of) with classical "network" service, but takes 85 minutes to boot...

We tried some parameters in system.conf about timeout, but no luck. Is there something wrong ?