[X2Go-User] HOWTO - install ubuntu & x2goserver inside inside LXC containers

[brian mullan]

The following is a description of how to install Ubuntu & x2go server
inside Linux Containers (LXC).

All of the following was done on an Ubuntu 12.04 server installed inside
LXC containers. These examples are only for a single container but you can
either Clone the first container you create and make necessary changes
regarding IP addresses (they will be different for each LXC container) or
start from scratch and create each manually.

If you are not familiar with LXC containers it is a very lightweight &
therefore very fast (faster than vmware, kvm, xen etc) technology built
into most modern Linux kernels and

distributions from Ubuntu, Debian, Fedora etc.    Note that LXC does not
support installing windows into an LXC container.


LXC allows you to provide complete isolation of one container from another
by default.

However, you can as an admin provide more or less isolation between
containers and also between containers and the HOST computer OS.

I will NOT go into how LXC works here as there is a lot of information on
the web which can help you understand more if you do a google search for
"lxc containers" or read some of the "references" I've put at the end of
this email.


Ubuntu 12.04 has made LXC very easy to use.   Canonical has simplified many
things to the extreme.   Other linux distributions
may/will differ on how you create, access etc LXC containers.

But lets begin creating our first LXC container and then we will install
Bonitasoft inside that container.

*STEP 1*

Assuming you are using Ubuntu 12.04 Desktop we will install LXC first the
create our first container which we will call x2goserver1-lxc.   In the

following we are going to use an “ubuntu” lxc template.    There are other
“lxc templates” for debian, fedora, centos etc that you could use if

you wanted to install one of those OS inside an LXC Container even if the
host is Ubuntu

 NOTE:   you can install any Linux OS into an LXC container the only major
rule is that the Linux must use the same Kernel as the Host linux.


*     sudo apt-get install lxc*



Next create the LXC container we are calling x2goserver1-lxc then start up
that container:

* *

*     sudo lxc-create -t ubuntu -n x2goserver1-lxc*

*     sudo lxc-start -n x2goserver1-lxc*

The “create” command above will create a new container called
"x2goserver1-lxc" and install ubuntu ... using the same version
of Ubuntu as your host computer so it will install ubuntu 12.04 inside the
LXC container named "x2goserver1-lxc"


This will take some time as it downloads all the required files from the
Ubuntu repositories and installs them to create a
bootable Ubuntu 12.04 system.

The “start” command above will actually start the LXC container called
"x2goserver1-lxc" and its Ubuntu system and leave you
at a terminal command prompt inside the LXC container.

*Note:*  that the command prompt will be different from a terminal on your
HOST computer as you will now be *inside* the
container and because we haven't added any additional user accounts yet the
login USERID will be the default which

is "ubuntu".

The command prompt should look something like the following:

     *ubuntu at x2goserver1-lxc:~$*

Create a User Accounts for the users that will be using this container:

     *sudo adduser user-name1*

*     etc.*


*STEP 2*

While logged into the container and at the terminal prompt install whatever
other tools you usually use.

In my case, because I wanted to see if x2go would work so I installed the
ubuntu desktop and the x2go server components.

 Install the Ubuntu Desktop:

      *sudo apt-get install ubuntu-desktop*

when this completes reboot Ubuntu in the LXC container:

      *sudo shutdown -r now*

this will reboot ubuntu in the container so the desktop environment will be
available.   Login again and continue.


Next install the x2go "server" side applications so I can later access the
container using the x2goclient on my HOST PC.

Next add the x2go repository:

*      sudo add-apt-repository ppa:x2go/stable*

*      sudo apt-get update*

Install the x2go "server" side components:

*      sudo apt-get install x2goserver
      sudo apt-get install x2goserver-session*

 On your HOST computer install the x2go client:

*      sudo add-apt-repository ppa:x2go/stable
      sudo apt-get update
      sudo apt-get install x2goclient*


 *STEP 3*

This step is important if you want to be able to access the LXC container
from the host using SSH or whatever other tools you use.

 The genesis of this step is from Stephane Graber who has taught me alot
about LXC from his blog.

This step is:


   1. performed outside of your linux container and must be done for the
   USER that will be accessing the x2goserver1-lxc.
   2. will require that you know the container IP address.   Each LXC
   container will have a different IP address even though they are all running
   on the same PC
   3. is necessary to allow someone on the HOST computer to access a
   container using the container's name with something like SSH etc.  for
   example in our case "ssh userID-on-x2goserver1 at x2goserver1-lxc"  will
   log the user-of-bos1-name into the container and leave them at a terminal
   prompt

*Add the following to each users ~/.ssh/config file. Note you may have to
create ~/.ssh/config if it doesn't yet exist and change the lxc-container
IP address to the container that each user is assigned to work with.**
*
note:  each of the following should be a single line entry

Host *.lxc StrictHostKeyChecking no UserKnownHostsFile /dev/null
ProxyCommand nc $(host $(echo %h | sed "s/\\\\.lxc//g") *
my-lxc-container-ip-address* | tail -1 | awk '{print $NF}') %p

Host *.libvirt StrictHostKeyChecking no UserKnownHostsFile /dev/null
ProxyCommand nc $(host $(echo %h | sed "s/\\\\.libvirt//g") *
my-host-ip-address* | tail -1 | awk '{print $NF}') %p



>From now on you can access the x2goserver1-lxc container using either SSH
or the x2go client



*STEP 4*

If you want to use x2go start the x2goclient, then on the HOST create a new
x2go "session" and add info about what LXC container IP address you want to
connect to, what desktop (unity, gnome etc) and what speed is the
connection (change this by moving the slider to LAN since we want the
fastest/no compression) and then save.

 Start the x2goclient session and log into the LXC container.   From now on
you can do everything as if you were on your HOST PC.

 Just remember you will be inside the LXC container so you are separated
from your host and changes made will only be  to the LXC container's Ubuntu.


 *PARTING THOUGHTS*

The reason for doing all of this?    Well there are several I can think of
but I’ll just name a couple:

   1. Linux is now available on ARM.    ARM cpu’s don’t support h/w
   virtualization solutions like vmware, kvm, xen etc.  but since LXC does
   NOT require h/w virtualization you can use LXC containers to provide
   different and isolated compute environments even on ARM computers.
   2.  LXC is much faster than vmware, kvm, xen because there is no h/w
   virtualization and because its part of the linux kernel each container can
   have as much or as little direct access to the HOST PC resources as you
   want to configure (read up about LXC CGROUPS).
   3.  Whereas Vmware, kvm, xen etc all require at least one dedicated cpu
   “core” for each virtual machine you can only run so many VMs concurrently
   on a system..  LXC does not have this restriction so with LXC there are
   many people running as many as 50-80 LXC containers on a single server
   although your mileage may vary depending on what each container has
   installed, how much CPU, memory etc is available.
   4. Maybe you’d like to have multiple customers each with an x2goserver
   but isolated from each other without resorting to the expense of separate
   servers for each customer?
   5. Web Servers often don’t really need dedicated servers or even
   dedicated Virtual Machines.    LXC Containers works great for that
   purpose.

 Remember I said that LXC containers can be as isolated from each other and
from the HOST as you want.   They start totally isolated but we changed
that a bit above so you could ssh or x2go into a container by adding the 2
statements to a users ~/.ssh/config file

However, you can allow LXC containers to share a HOST file
system/directory, or even a something like an SQL server running on the
HOST (again read about LXC CGROUPS).

I may have forgotten a step or mistyped something here and if so send me a
note and I'll double check and make any addition/correction.

Have fun...


*References:*
http://lxc.teegra.net/
http://www.ibm.com/developerworks/linux/library/l-lxc-containers/
http://www.stgraber.org/category/lxc/

Brian Mullan
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