LXC Container Networking
- by digitaladdictions
I just started to experiment with LXC containers. I was able to create a container and start it up but I cannot get dhcp to assign the container an IP address. If I assign a static address the container can ping the host IP but not outside the host IP.
The host is CentOS 6.5 and the guest is Ubuntu 14.04LTS. I used the template downloaded by lxc-create -t download -n cn-01 command.
If I am trying to get an IP address on the same subnet as the host I don't believe I should need the IP tables rule for masquerading but I added it anyways. Same with IP forwarding.
I compiled LXC by hand from the following source https://linuxcontainers.org/downloads/lxc-1.0.4.tar.gz
Host Operating System Version
#> cat /etc/redhat-release
CentOS release 6.5 (Final)
#> uname -a
Linux localhost.localdomain 2.6.32-431.20.3.el6.x86_64 #1 SMP Thu Jun 19 21:14:45 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
Container Config
#> cat /usr/local/var/lib/lxc/cn-01/config
# Template used to create this container: /usr/local/share/lxc/templates/lxc-download
# Parameters passed to the template:
# For additional config options, please look at lxc.container.conf(5)
# Distribution configuration
lxc.include = /usr/local/share/lxc/config/ubuntu.common.conf
lxc.arch = x86_64
# Container specific configuration
lxc.rootfs = /usr/local/var/lib/lxc/cn-01/rootfs
lxc.utsname = cn-01
# Network configuration
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0
LXC default.confu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:12:30:f2 brd ff:ff:ff:ff:f
#> cat /usr/local/etc/lxc/default.conf
lxc.network.type = veth
lxc.network.link = br0
lxc.network.flags = up
#> lxc-checkconfig
Kernel configuration not found at /proc/config.gz; searching...
Kernel configuration found at /boot/config-2.6.32-431.20.3.el6.x86_64
--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
User namespace: enabled
Network namespace: enabled
Multiple /dev/pts instances: enabled
--- Control groups ---
Cgroup: enabled
Cgroup namespace: enabled
Cgroup device: enabled
Cgroup sched: enabled
Cgroup cpu account: enabled
Cgroup memory controller: /usr/local/bin/lxc-checkconfig: line 103: [: too many arguments
enabled
Cgroup cpuset: enabled
--- Misc ---
Veth pair device: enabled
Macvlan: enabled
Vlan: enabled
File capabilities: /usr/local/bin/lxc-checkconfig: line 118: [: -gt: unary operator expected
Note : Before booting a new kernel, you can check its configuration
usage : CONFIG=/path/to/config /usr/local/bin/lxc-checkconfig
Network Config (HOST)
#> cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
#> cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
TYPE=Ethernet
IPV6INIT=no
USERCTL=no
BRIDGE=br0
#> cat /etc/networks
default 0.0.0.0
loopback 127.0.0.0
link-local 169.254.0.0
#> ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:12:30:f2 brd ff:ff:ff:ff:ff:ff
inet6 fe80::20c:29ff:fe12:30f2/64 scope link
valid_lft forever preferred_lft forever
3: pan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN
link/ether 42:7e:43:b3:61:c5 brd ff:ff:ff:ff:ff:ff
4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
link/ether 00:0c:29:12:30:f2 brd ff:ff:ff:ff:ff:ff
inet 10.60.70.121/24 brd 10.60.70.255 scope global br0
inet6 fe80::20c:29ff:fe12:30f2/64 scope link
valid_lft forever preferred_lft forever
12: vethT6BGL2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether fe:a1:69:af:50:17 brd ff:ff:ff:ff:ff:ff
inet6 fe80::fca1:69ff:feaf:5017/64 scope link
valid_lft forever preferred_lft forever
#> brctl show
bridge name bridge id STP enabled interfaces
br0 8000.000c291230f2 no eth0
vethT6BGL2
pan0 8000.000000000000 no
#> cat /proc/sys/net/ipv4/ip_forward
1
# Generated by iptables-save v1.4.7 on Fri Jul 11 15:11:36 2014
*nat
:PREROUTING ACCEPT [34:6287]
:POSTROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A POSTROUTING -o eth0 -j MASQUERADE
COMMIT
# Completed on Fri Jul 11 15:11:36 2014
Network Config (Container)
#> cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
#> ip a s
11: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 02:69:fb:42:ee:d7 brd ff:ff:ff:ff:ff:ff
inet6 fe80::69:fbff:fe42:eed7/64 scope link
valid_lft forever preferred_lft forever
13: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
