systemd-networkd on Ubuntu 16.04 LTS (Xenial)
My OpenStack cloud depends on Ubuntu, and the latest release of OpenStack-Ansible (what I use to deploy OpenStack) requires Ubuntu 16.04 at a minimum. I tried upgrading the servers in place from Ubuntu 14.04 to 16.04, but that didn’t work so well. Those servers wouldn’t boot and the only recourse was a re-install.
Once I finished re-installing them (and wrestling with several installer bugs in Ubuntu 16.04), it was time to set up networking. The traditional network configurations in
/etc/network/interfaces are fine, but they weren’t working the same way they were in 14.04. The VLAN configuration syntax appears to be different now.
But wait - 16.04 has systemd 229! I can use systemd-networkd to configure the network in a way that is a lot more familiar to me. I’ve made posts about systemd-networkd before and the simplicity in the configurations.
I started with some simple configurations:
root@hydrogen:~# cd /etc/systemd/network root@hydrogen:/etc/systemd/network# cat enp3s0.network [Match] Name=enp3s0 [Network] VLAN=vlan10 root@hydrogen:/etc/systemd/network# cat vlan10.netdev [NetDev] Name=vlan10 Kind=vlan [VLAN] Id=10 root@hydrogen:/etc/systemd/network# cat vlan10.network [Match] Name=vlan10 [Network] Bridge=br-mgmt root@hydrogen:/etc/systemd/network# cat br-mgmt.netdev [NetDev] Name=br-mgmt Kind=bridge root@hydrogen:/etc/systemd/network# cat br-mgmt.network [Match] Name=br-mgmt [Network] Address=172.29.236.21/22
Here’s a summary of the configurations:
- Physical network interface is
- VLAN 10 is trunked down from a switch to that interface
br-mgmtshould be on VLAN 10 (only send/receive traffic tagged with VLAN 10)
Once that was done, I restarted systemd-networkd to put the change into effect:
# systemctl restart systemd-networkd
Great! Let’s check our work:
root@hydrogen:~# brctl show bridge name bridge id STP enabled interfaces br-mgmt 8000.0a30a9a949d9 no root@hydrogen:~# networkctl IDX LINK TYPE OPERATIONAL SETUP 1 lo loopback carrier unmanaged 2 enp2s0 ether routable configured 3 enp3s0 ether degraded configured 4 enp4s0 ether off unmanaged 5 enp5s0 ether off unmanaged 6 br-mgmt ether no-carrier configuring 7 vlan10 ether degraded unmanaged 7 links listed.
So the bridge has no interfaces and it’s in a
no-carrier status. Why? Let’s check the journal:
# journalctl --boot -u systemd-networkd Jan 15 09:16:46 hydrogen systemd: Started Network Service. Jan 15 09:16:46 hydrogen systemd-networkd: br-mgmt: netdev exists, using existing without changing its parameters Jan 15 09:16:46 hydrogen systemd-networkd: br-mgmt: Could not append VLANs: Operation not permitted Jan 15 09:16:46 hydrogen systemd-networkd: br-mgmt: Failed to assign VLANs to bridge port: Operation not permitted Jan 15 09:16:46 hydrogen systemd-networkd: br-mgmt: Could not set bridge vlan: Operation not permitted Jan 15 09:16:59 hydrogen systemd-networkd: enp3s0: Configured Jan 15 09:16:59 hydrogen systemd-networkd: enp2s0: Configured
Could not append VLANs: Operation not permitted error is puzzling. After some searching on Google, I found a thread from Lennart:
After an upgrade, systemd-networkd is broken, exactly the way descibed > in this issue #3876 Please upgrade to 231, where this should be fixed. Lennart
But Ubuntu 16.04 has systemd 229:
# dpkg -l | grep systemd ii libpam-systemd:amd64 229-4ubuntu13 amd64 system and service manager - PAM module ii libsystemd0:amd64 229-4ubuntu13 amd64 systemd utility library ii python3-systemd 231-2build1 amd64 Python 3 bindings for systemd ii systemd 229-4ubuntu13 amd64 system and service manager ii systemd-sysv 229-4ubuntu13 amd64 system and service manager - SysV links
I haven’t found a solution for this quite yet. Keep an eye on this post and I’ll update it once I know more!
#networking #openstack #systemd #systemd-networkd #ubuntu