Translation(s): none


Please find alternative network setups for containers on the LXC mainpage.

VLAN + bridge + LXC

host configuration

Assuming the host is on a regular private local network, and you place the guest inside the .123 VLAN, here's what /etc/network/interfaces may look like :

auto eth0
iface eth0 inet static
        address 192.168.1.12
        netmask 255.255.255.0
        gateway 192.168.1.1
        dns-nameservers 192.168.1.1

iface eth0.123 inet manual

auto br0.123
iface br0.123 inet manual
      bridge_ports eth0.123
      bridge_fd 0
      bridge_maxwait 0

VLAN configuration is part of the vlan package and is described in the vlan-interfaces(5) man page (which also describes alternative configuration formats). The bridge_* options are in bridge_utils_interfaces(5), part of bridge-utils. Descriptions of Linux VLANs and bridging.

IP address on the bridge

Alternatively, one may place the IP address on the bridge instead of the physical device, so the configuration becomes:

iface eth0.123 inet manual

auto br0.123
iface br0.123 inet static
    bridge_...
    ...
    address ...

There is no explicit eth0 line.

guest configuration

Then, you'd configure the LXC container/guest with something like :

lxc.utsname = guestvm
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0.123
lxc.network.name = eth0
lxc.network.ipv4 = 192.168.2.1/24
lxc.network.veth.pair = vethvm1

where 192.168.2.x would be on the 123 VLAN.

To the guest, this will then be transparent : inside the guest, a single eth0 will be available, with 192.168.2.1/24 IP address (and no VLAN).

You'll probably need ebtables firewalling to control the traffic through the bridge.

Attention : if you receive the following message inside the guest upon network start : RTNETLINK answers: File exists, then you may need to comment the lxc.network.ipv4 line in the guest's config, and add a full auto eth0 + iface eth0 inet static ... inside the guest's /etc/network/interfaces (the guest's ifupdown's network configuration on boot will try to up an already up interface which has already been set to an IP, hence the error message).

(VLAN + bridge + LXC) x n

Instructions for adding more VLANs/bridges/LXCs.

host configuration

Create one bridge with an IP address, as above:

iface eth0.123 inet manual

auto br0.123
iface br0.123 inet static
    bridge_...
    ...
    address ...

For each additional VLAN + bridge pair, add them without an address:

iface eth0.124 inet manual

auto br0.124
iface br0.124 inet manual
    bridge_...

guest configuration

Containers are configured as in the one-VLAN case.

With multiple bridges, it becomes possible to configure a container with multiple ports, each connected to a different bridge (and thus, typically, a different VLAN). (Of course it's also possible—though fairly pointless—to connect multiple ports to the same bridge.) See lxc.conf(5) for details.