How to Manage Linux Containers using LXC

Linux Containers  is a light weight virtualization technology at the operating-system level which is capable of running more than one Linux system on a Linux host. It is an alternative to other traditional hypervisors like KVM and Xen.  Compared to the full machine virtualization techniques, isolation offered in containers is less but at the same time overhead is reduced as a portion of the host kernel and operating system instance gets shared by the virtual machines.  This does not mean that the containers can replace traditional hypervisors as each have their own pros and cons. In this article, we will briefly learn about the installation and usage of one of the popular Linux based container project LXC.

Installation of LXC

I'm using Ubuntu 14.10 for all the examples used here.

LXC can be installed by using the simple apt-get command in Debian based distros (yum in RedHat based ones).  Make sure that you use 'sudo' command everywhere if you are not logged in as root.

sudo apt-get install lxc

Creation, listing, login and stopping

Next you need to create a container by using the lxc-create command

sudo lxc-create -t  <template> -n <container-name>

There are quite a few ready-made templates available for creating containers. They are mostly for the popular Linux distributions. Let us try to create a Ubuntu based container.

sudo lxc-create -t ubuntu -n Ubuntu1

May be you want to help yourself with a cup of coffee as it takes a while for retrieving the required packages and creating the container. :)

lxc-create comand
Output of 'lxc-create' command
lxc-create command
Output of 'lxc-create' command - contd....

Now we have an Ubuntu container with the name Unbuntu1.

Let us now list all the containers that are present on our host.

sudo lxc-ls
poornima@poornima-Lenovo:~$ sudo lxc-ls
[sudo] password for poornima:

We can view the complete details using lxc-info

sudolxc-info -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-info -n Ubuntu1
Name: Ubuntu1

From the output you can see the list of all the containers present on the host and categorised depending on the different states that they are in (running, stopped or frozen).

Containers can be started using the lxc-start command.

lxc-start -n <container-name>


lxc-start -d -n <container-name>    to start the container in the background.

Verify if the container has actually started or not:

poornima@poornima-Lenovo:~$ sudo lxc-info -n Ubuntu1
Name: Ubuntu1
PID: 2969
CPU use: 1.27 seconds
BlkIO use: 20.66 MiB
Memory use: 26.27 MiB
KMem use: 0 bytes
Link: vethVFLSOP
TX bytes: 1.80 KiB
RX bytes: 4.94 KiB
Total bytes: 6.74 KiB

In order to login or attach back to the container console, we have lxc-console. 

lxc-console -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-console -n Ubuntu1

Connected to tty 1
Type <Ctrl+a q> to exit the console, <ctrl+a ctrl+a=""> to enter Ctrl+a itself

Ubuntu 14.10 Ubuntu1 tty1

Ubuntu1 login: ubuntu
Last login: Thu Aug 27 12:05:59 IST 2015 on lxc/tty1
Welcome to Ubuntu 14.10 (GNU/Linux 3.16.0-23-generic i686)

* Documentation:

We can come back to the host's console using the key sequence 'Ctrl+a' followed q.  Note that the container is still running in the background and we have just detached from it.

If you have to stop the container you need to use lxc-stop.

lxc-stop -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-stop -n Ubuntu1
poornima@poornima-Lenovo:~$ sudo lxc-info -n Ubuntu1
Name: Ubuntu1

Freezing, unfreezing, cloning and poweroff

Containers can be frozen using the lxc-freeze command.

lxc-freeze -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-freeze -n Ubuntu1
poornima@poornima-Lenovo:~$ sudo lxc-info -n Ubuntu1
Name: Ubuntu1
PID: 2969
CPU use: 1.48 seconds
BlkIO use: 21.42 MiB
Memory use: 26.96 MiB
KMem use: 0 bytes
Link: vethVFLSOP
TX bytes: 2.63 KiB
RX bytes: 5.80 KiB
Total bytes: 8.43 KiB

You can unfreeze them with lxc-unfreeze. 

 lxc-unfreeze -n <container-name>

One can even clone containers using the lxc-clone command. But before issuing the clone command, see to it that you stop the running container first using the lxc-stop command as mentioned previously.

lxc-clone -o <existing container> -n <new container>
poornima@poornima-Lenovo:~$ sudo lxc-clone -o Ubuntu1 -n Ubuntu-clone
Created container Ubuntu-clone as copy of Ubuntu1
poornima@poornima-Lenovo:~$ sudo lxc-ls
Ubuntu-clone Ubuntu1

To poweroff containers, use lxc poweroff when inside the containers console.

ubuntu@Ubuntu1:~$ sudo poweroff
[sudo] password for ubuntu:

Broadcast message from ubuntu@Ubuntu1
(/dev/lxc/tty1) at 12:17 ...

The system is going down for power off NOW!

You can verify from the host that the container has stopped.

poornima@poornima-Lenovo:~$ sudo lxc-info -n Ubuntu1
Name: Ubuntu1

Snapshots - creation and restoration

lxc-snapshot command is useful for taking a snapshot of the required container.

lxc-snapshot  -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-snapshot -n Ubuntu1
lxc_container: lxccontainer.c: lxcapi_snapshot: 2953 Snapshot of directory-backed container requested.
lxc_container: lxccontainer.c: lxcapi_snapshot: 2954 Making a copy-clone. If you do want snapshots, then
lxc_container: lxccontainer.c: lxcapi_snapshot: 2955 please create an aufs or overlayfs clone first, snapshot that
lxc_container: lxccontainer.c: lxcapi_snapshot: 2956 and keep the original container pristine.

These snapshots will be stored under /var/lib/lxc in Ubuntu 14.10 . In some earlier versions, you can find them in /var/lib/lxcsnaps. 

poornima@poornima-Lenovo:~$ sudo lxc-snapshot --name Ubuntu1 --list
snap0 (/var/lib/lxc/Ubuntu1/snaps) 2015:08:27 12:20:41

Configuration options

By default, all the containers created using lxc are stored under /var/lib/lxc where each container will have a directory. Inside this directory, each containers configuration will be stored in a file called config. The option  lxc.rootfs specifies the location of containers root file system.  lxc. network.type specifies the kind of networking used by that container. Eg, veth

If you are interested in more configuration options, check out man 5 lxc.conf


Containers can be completely destroyed from the host using lxc-destroy command. If you have created any snapshots from the container that you are about to delete, you need to first delete them.

lxc-destroy -n <container-name>
poornima@poornima-Lenovo:~$ sudo lxc-destroy --name=Ubuntu-clone
poornima@poornima-Lenovo:~$ sudo lxc-info --name=Ubuntu-clone
Ubuntu-clone doesn't exist

Management using web console

If you are not a fan of the Linux command line or not comfortable using it, then you can manage your containers using the LXC web panels through your browsers.

Install the web panel using the following command as a root user.

wget -O - | bash
root@poornima-Lenovo:/home/poornima# wget -O - | bash
--2015-08-27 13:15:13--
Resolving (
Connecting to (||:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2678 (2.6K) [application/x-sh]
Saving to: STDOUT

0% [                                                                                                                                                                     ] 0 --.-K/s _ __ _______ __ __ _ _____ _
| | \ \ / / ____| \ \ / / | | | __ \ | |
| | \ V / | \ \ /\ / /__| |__ | |__) |_ _ _ __ ___| |
| | > <| | \ \/ \/ / _ \ '_ \ | ___/ _` | '_ \ / _ \ |
| |____ / . \ |____ \ /\ / __/ |_) | | | | (_| | | | | __/ |
|______/_/ \_\_____| \/ \/ \___|_.__/ |_| \__,_|_| |_|\___|_|
Automatic installer

Installing requirement...
100%[======================================>] 2,678 --.-K/s in 0.003s

2015-08-27 13:15:14 (867 KB/s) - written to stdout [2678/2678]

Cloning LXC Web Panel...
Cloning into '/srv/lwp'...
remote: Counting objects: 188, done.
remote: Total 188 (delta 0), reused 0 (delta 0), pack-reused 188
Receiving objects: 100% (188/188), 172.76 KiB | 49.00 KiB/s, done.
Resolving deltas: 100% (79/79), done.
Checking connectivity... done.

Installation complete!
Adding /etc/init.d/lwp...
Starting server...done.
Connect you on http://your-ip-address:5000/

We can then access the user interface using the URL:  http://:5000 using the default userid / password  admin/admin

LXC web panel login screen
LXC Web panel login screen
Web panel
LXC web panel User Interface

Phew! Now, you are ready to perform all your container related operations using the web panel!!


In this article, we have learnt how to install LXC, use some of the available commands and the web panel. Of late, some tools have been developed which in turn use LXC underneath.  Docker engine and LXD are some of them.  In the near future, it is quite possible for the cloud infrastructure to heavily use Linux containers for all the advantages they have to offer.

1 thought on “How to Manage Linux Containers using LXC”... add one

Leave a Comment