The boot process of a thin client
Load the Linux kernel into the memory of the thin client. This can be done several different ways, including:
Each of the above booting methods will be explained later in this chapter. But for now, it should be noted that it makes sense in almost all cases to use a PXE based network card during booting for the fastest, and easiest to setup method.
Once the kernel has been loaded into memory, it will begin executing.
The kernel will initialize the entire system and all of the peripherals that it recognizes.
This is where the fun really begins. During the kernel loading process, an initramfs image will also be loaded into memory.
Normally, when the kernel is finished booting, it will launch the new task launcher `upstart`, which will handle starting up a server or workstation. But, in this case, we've instructed the kernel to load a small shell script instead. This shell script is called `/init`,and lives in the root of the initramfs.
The `/init` script begins by mounting and , starts `udev` to discover and initialize hardware, especially the network card, which is needed for every aspect of the boot from here on. As well, it creates a small ram disk, where any local storage that is needed (to configure the file, for instance) can be written to.
The network interface is configured. This is the networking interface that has as its IP address.
A small DHCP client called `ipconfig` will then be run, to make another query from the DHCP server. This separate user-space query gets information supplied in the dhcpd.conf file, like the nfs root server, default gateway, and other important parameters.
When `ipconfig` gets a reply from the server, the information it receives is used to configure the Ethernet interface, and determine the server to mount the root from.
Up to this point, the root filesystem has been a ram disk. Now, the `/init` script will mount a new root filesystem via either NBD or NFS. In the case of NBD, the image that is normally loaded is . If the root is mounted via NFS, then the directory that is exported from the server is typically . It can't just mount the new filesystem as . It must first mount it to a separate directory. Then, it will do a `run-init`, which will swap the current root filesystem for a new filesystem. When it completes, the filesystem will be mounted on . At this point, any directories that need to be writable for regular start up to occur, like , or , are mounted at this time.
Once the mounting of the new root filesystem is complete, we are done with the `/init` shell script and we need to invoke the real `/sbin/init` program.
The `init` program will read the directory and begin setting up the thin client environment. From there, upstart will begin reading the start up commands in .
It will execute the `ltsp-client-setup` command which will configure many aspects of the thin client environment, such as checking if local devices need starting, loading any specified modules, etc.
Next, the `init` program will begin to execute commands in the directory
One of the items in the directory is the `ltsp-client-core` command that will be run while the thin client is booting.
The file will be parsed, and all of the parameters in that file that pertain to this thin client will be set as environment variables for the `ltsp-client-core` script to use.
If Sound is configured at this point, the `pulseaudio` daemon is started, to allow remote audio connections from the server to connect and play on the thin client.
If the thin client has local device support enabled, the `ltspfsd` program is started to allow the server to read from devices such as memory sticks or CD-Roms attached to the thin client.
At this point, any of the screen sessions you've defined in your will be executed.
Screen sessions are what you want to launch on all of the virtual screens on your terminal. These are the standard virtual screens that all GNU/Linux distributions usually have, i.e. , through .
By default, a standard character based getty will be run on screen 1 ( in the file).
As well, if nothing else is specified in the file, an `ldm`ldm; screen script is run on . The LTSP Display Manager (`ldm`ldm;) is the default login manager for LTSP.
If is set to a value of `ldm`ldm;, or `startx`, then the X Windows System will be launched, giving you a graphical user interface.
By default, the Xorg server will auto-probe the card, create a default file on the ram-disk in the terminal, and start up xorg with that custom config.
The X server will either start an encrypted `ssh` tunnel to the server, in the case of `ldm`ldm;, or an an XDMCP query to the LTSP server, in the case of `startx`. Either way, a login box will appear on the terminal.
At this point, the user can log in. They'll get a session on the server.
This confuses a lot of people at first. They are sitting at a thin client, but they are running a session on the server. All commands they run will be run on the server, but the output will be displayed on the thin client.
With the integration of LTSP into distributions, installation of LTSP is now usually as easy as adding the LTSP packages in your distro's package manager. Consult your distribution's documentation for details on how to install LTSP on your particular system.
However, as a general guideline, usually after you've installed your distributions' LTSP packages, and configured your network interfaces, and some kind of DHCP3 server, you'd run (as root):
If you are on a 64-bit system but your clients have another architecture use the --arch option e.g.
After that, you should be able to boot your first thin client.
General thin client parameters
There are several variables that one can define in the lts.conf file which control how the thin client interacts with the server. These are:
Modules and startup scripts
For the most part, LTSP does a very good job of detecting what hardware's on your thin client. However, it's possible that you may want to manually specify a kernel module to load after boot. Alternatively, you may have a script you've written that you've put in the chroot, and want to make sure gets run at startup. LTSP provides some hooks to allow you to do this.
Sound in LTSP
Sound in LTSP is handled by running the `pulseaudio` daemon on the thin client, which sits on top of the ALSA kernel drivers. The thin client's kernel should detect the thin client sound hardware via the usual udev mechanisms, and enable the sound card. At boot time, the `pulseaudio` daemon is run, which allows the thin client to receive audio streams via network connections.
On login, the LDM sets both the and environment variables for the X windows session, to allow the server to re-route the sound over a TCP/IP socket to the thin client.
Setting up X windows on the thin client's normally a pretty easy operation. The thin client uses X.org's own auto configuration mode to let X determine what it thinks is installed in the box.
However, sometimes, this doesn't always work. Either due to strange/buggy hardware, or buggy drivers in X.org, or because X detects default settings that you don't want. For instance, it may detect that your monitor is capable of doing 1280x1024, but you'd prefer it to come up in 1024x768 resolution. Fortunately, you can tweak individual X settings, or, alternatively, simply provide your own to use.
XRANDR setting for managing displays
The new Xorg Xserver has the ability to figure out (for the most part, to the extent that the driver helps in the process) the best mode for the videocard. Moreover, with the new dependency upon hal and Xrandr, it is recommended to add input devices with hal and modify video modes with Xrandr 1.2 calls. In essence, the xorg.conf becomes a place really to fix deficiencies in poorly written drivers or to force certain abnormal driver behavior in a particular environment in a way that can not be otherwise done through hal or Xrandr.
New Xorg structure within LTSP
To accommodate this, Xorg now understands partial xorg.conf files. Meaning you only add the sections that you need to force. Otherwise, it discovers everything. That's why you might see minimalist xorg.conf files in your LTSP chroot.
The directory (located in the chroot's ) is a structure of shell scripts all of which are sourced in order (similar to or that you may be familiar with). These scripts are executed upon the beginning of each session but before the Xserver (if the session runs an Xserver) is launched. You can make whatever script you want that may need to run at that point. For LTSP, one thing we use it for is to set up the Xserver will be launched. This entails not just generating a file as needed, but also configuring the parameters that the Xserver should be launched with. The nice thing about a collection of sourced scripts is that it gives flexibility to the distribution or to the administrator to add additional scripts that may be required for that distribution or for a particular network environment that will not modify existing files (and therefore require more maintenance to care for updates in the upstream code).
Each script is named with a prefix letter, then an order number, then a name. The prefix letter determines when the scripts of that prefix are executed and the order number determines in what order.
PREFIXES: Prefixes that may be used include:
S - Is a script that runs at the beginning of a session (screen script) K - Is a script that runs at the end of a session (screen script) XS - Is a script that is only run at the beginning of screen scripts that run an Xserver
All of the scripts that generate a xorg.conf or modify the Xserver arguments are XS* scripts.
These scripts are mostly organized by the particular lts.conf parameter or function that they affect. For example, XS85-xvideoram adds the ability to specify the X_VIDEO_RAM parameter in lts.conf and force the amount of video ram used by the driver.
If you are going to create your own script, I recommend looking at other scripts to understand the structure. Since many hacks may impact the same xorg.conf sections, each section has a function of hacks assigned to it, and in your script, you would create a function and add it to the list of functions for that section. For example, if you add something to the Monitor section (that cannot already be added through existing functions) you would create a function in your script and add it to the monitor_hacks function list. Again, easier to read the code and look at examples to understand how to write a new script.
Also, please note that one of the lts.conf parameters you can specify is: This should be set to a path to a script. So, if you have the old configure-x.sh and like it better, simply copy it into the chroot, to say, `/opt/ltsp/<arch>/usr/share/ltsp/configure-x.sh` and then in , specify: and you will be back to where you were.
Description to be added later.
Description to be added later.
The LDM display manager
The LTSP Display Manager, or `ldm`ldm; is the display manager specifically written by the LTSP project to handle logins to a GNU/Linux server. It is the default display manager for LTSP thin clients running under LTSP, and has a lot of useful features:
It is written in C, for speed and efficiency on low end clients.
It supports logging in via either a greeter (a graphical login application) or autologin.
It can be configured to encrypt X Windows traffic, for increased security, or leave it unencrypted, for better performance on slower clients.
It contains a simple load-balancing system, to allow the system administrator to allow load balancing across several servers.
We'll go over the entries you'll need to control these features below.
Theory of operation
To help understand the following sections, a bit of an explanation of how `ldm`ldm; does it's work is needed. Most thin client display managers tend to run up on the server. The `ldm`ldm; display manager is unique in that it runs on the thin client itself. This allows the thin client to have a lot of choice as to how it will set up the connection. A typical login session goes as follows:
`ldm`ldm; launches and starts up the X Windows display on the thin client.
`ldm`ldm; starts up the greeter, which is a graphical program which presents the user with a nice login display and allows them to select their session, language, and host they'd like to log into.
`ldm`ldm; collects the information from the greeter, and starts an ssh session with the server. This ssh connection is used to create an ssh master socket, which is used by all subsequent operations.
Now, the users selected session is started via the master socket. Depending on whether or not an encrypted connection has been requested, via the parameter, the session is either connected back to the local display via the ssh tunnel, or via a regular TCP/IP connection.
During the session, any memory sticks, or other local devices that are plugged in, communicate their status to the server via the ssh control socket.
When the user exits the session, the ssh connection is closed down, the X server is stopped, and `ldm`ldm; restarts itself, so everything starts with a clean slate.
Encrypted versus unencrypted sessions
By default, LTSP5 encrypts the X session between the server. This makes your session more secure, but at the cost of increased processing power required on the thin client and on the server. If processing power is a concern to you, it's very easy to specify that the connection for either an individual workstation, or the default setting should use an unencrypted connection. To do so, simply specify:
in your file in the appropriate section.
Load balancing features
In this version of LTSP, there's a simple load-balancing solution implemented that allows administrators to have multiple LTSP servers on the network, and allow the thin client to pick which one of the servers it would like to log into.
The host selection system is simple and flexible enough to allow administrators to implement their own policy on how they want the load balancing to happen: either on a random, load-based, or round robin system. See for details.
RC script capabilities
LDM has a very good system for handling user-supplied rc.d scripts. This allows people looking to add site-specific customizations to their LTSP setups an easy way to integrate this functionality into LTSP.
These rc.d scripts can be placed in . They are executed in the usual rc.d type method, so you must make sure that any script you write will not make a call to `exit`.
The files start with the letter I, S, K, or X, and have two digits after them, allowing you to place them in order of execution. The letters stand for:
scripts are executed at the start of LDM, before the greeter has been presented.
scripts are executed after the user has logged in, but before the X session is run.
scripts are executed while the X session is being executed.
scripts are executed after the X session has ended, but before the user logs out entirely.
Your scripts can make use of the following environment variables in the S, X, and K scripts:
This is the username the user supplied at login.
The path to the ssh control socket that LDM has open for communication with the server.
The current server that LDM is connected to.
The IP address of the thin client.
You can use these variables to create scripts that customize behaviors at login time. For instance, lets say you were running the GNOME desktop environment, and wanted to force your users to have blank-only mode for their screen savers, to save network bandwidth.
Since the script is actually running , you want this script to set this up on the server, where the Gnome session is running. That's where you can make use of the and environment variables to run an `ssh` command on the server, using the control socket that LDM has set up. Here's an example script. You could install this into :
Using this mechanism, it's easy to customize your LTSP setup to your needs.
LDM lts.conf parameters
Multiple server setup
A multiple server setup is useful for larger thin client networks. Instead of using one big server, it makes it possible to use smaller servers, and dispatch users on them. You can adjust computing resources as the demand grows simply by adding a new server. To make sure that every server behaves the same from the users point of view, new services and configurations that are required will be discussed. In addition, some configurations specific to thin clients will be presented.
The network topology is the same as a standalone server setup, except that there are more than one server on the thin client LAN.
You will need to select one server to behave as the primary server. This server will be used to run additional services, hold users files, and network boot thin clients.
Secondary servers will be used only to run desktop sessions. They are simpler, and will be configured to use the central services from the primary server.
A user should be able to start a session with the same login and password, no matter which server it connects to. For this purpose, a central authentication mechanism must be used. There are many possibilities offered. Here are the major technologies:
LDAP authentication: On the master server, setup an OpenLDAP server. Configure each servers to use this LDAP server as the authentication base.
NIS authentication: On the master server, setup a NIS server. Configure each server to use this NIS server for the authentication.
Winbind authentication: Useful if you already have an Active Directory server.
For detailed instructions, see their respective manuals.
Shared home directories are easy to setup using an NFS server on eithe the primary LTSP server, or even better, a standalone NFS server. Other more modern, faster (and consequently more expensive) options include a SAN, and maybe even moving to a fibre-channel raid SAN. Consult your distribution's documentation for details and suggestions for setting up an NFS server.
Managing the SSH known hosts file
For security reasons, a thin client won't connect to an untrusted server. You must add the keys of secondary servers inside the client root on the primary server. To do this, first export the key file of the secondary server using LTSP's tools. As root, run:
Then, copy the file to the primary server, in the directory and run `ltsp-update-sshkeys` on the primary server. Then, thin clients will trust the freshly added server, and will be able to connect to it.
If a secondary server changes it's IP address, then this procedure must be repeated.
Setting Network Forwarding or Masquerading
The purpose of IP Masquerading is to allow machines with private, non-routable IP addresses on your network to access the Internet through the machine doing the masquerading. Traffic from your private network destined for the Internet must be manipulated for replies to be routable back to the machine that made the request. To do this, the kernel must modify the IP address of each packet so that replies will be routed back to it, rather than to the private IP address that made the request, which is impossible over the Internet. Linux uses (conntrack) to keep track of which connections belong to which machines and reroute each return packet accordingly. Traffic leaving your private network is thus "masqueraded" as having originated from your gateway machine. This process is referred to in Microsoft documentation as Internet Connection Sharing.
IP Forwarding with IP Tables
to enable IPv4 packet forwarding by editing /etc/sysctl.conf and uncomment the following line:
If you wish to enable IPv6 forwarding also uncomment:
Next, execute the sysctl command to enable the new settings in the configuration file:
IP Masquerading can now be accomplished with a single iptables rule, which may differ slightly based on your network configuration:
The above command assumes that your private address space is 192.168.0.0/16 and that your Internet-facing device is eth0. The syntax is broken down as follows:
Define the server list
LDM is a login manager for thin clients. Users can select a server from the available ones in the host selection dialogue box.
The displayed server list is defined by the parameter. This parameter accepts a list of server IP address or host names, separated by space. If you use host names, then your DNS resolution must work on the thin client. If defined in the file, the list order will be static, and the first server in the list will be selected by default.
You can also compute a new order for the server list, by creating the script `/opt/ltsp/<arch>/usr/share/ltsp/get_hosts` . The parameter overrides the script. In consequence, this parameter must not be defined if the `get_hosts` is going to be used. The `get_hosts` script writes on the standard output each server IP address or host names, in the chosen order.
You can change this behaviour by using a script to rearrange the list. The simplest way to do it is by randomizing the list. First, define a custom variable in the file , for example , that will contain the list of servers, the same way as Then, put the following script in `/opt/ltsp/<arch>/usr/share/ltsp/get_hosts`
More advanced load balancing algorithms can be written. For example, load balancing can be done by querying ldminfod for the server rating. By querying ldminfod, you can get the current rating state of the server. This rating goes from 0 to 100, higher is better. Here is an example of such a query:
Just like on a full fledged workstation, it helps to have swap defined for your thin client. "Swap" is an area of disk space set aside to allow you to transfer information out of ram, and temporarily store it on a hard drive until it's needed again. It makes the workstation look like it has more memory than it actually does. For instance, if your workstation has 64 Megabytes of ram and you configure 64 Megabytes of swap, it's theoretically possible to load a 128 Megabyte program.
We say, "theoretically", because in practice, you want to avoid swapping as much as possible. A hard drive is several orders of magnitude slower than ram, and, of course, on a thin client, you don't even have a hard drive! You have to first push the data through the network to the server's hard drive, thus making your swapping even slower. In practice, it's best to make sure you have enough ram in your thin client to handle all your average memory needs.
However, sometimes that's not possible. Sometimes, you're re-using old hardware, or you've simply got a program that isn't normally used, but does consume a lot of ram on the thin client when it does. Fortunately, LTSP supports swapping over the network via NBD, or Network Block Devices. We include a small shell script called nbdswapd, which is started via inetd. It handles creating the swap file, and setting up the swapping, and removing the swap file when it's no longer needed, after the terminal shuts down.
By default, swap files are 64 Megabytes in size. This was chosen to give your workstation a little extra ram, but not use up too much disk space. If you get some random odd behaviour, such as Firefox crashing when viewing web pages with a lot of large pictures, you may want to try increasing the size of the swap files. You can do so by creating a file in the directory on the LTSP server, called . In it, you can set the SIZE variable to the number of Megabytes you wish the file to be sized to. For instance, to create 128 Megabyte files, you'll want: SIZE=128 in the file.
Please note that this is a global setting for all swap files. If your server has 40 thin clients, each using 128 Megs of memory, you'll need 128 * 40 = 5120, or a little over 5 Gigabytes of space in your directory, where the swap files are stored.
DHCP stands for Dynamic Host Configuration Protocol and is the very first thing your thin client uses to obtain an IP address from the network, in order to allow it to start booting. In LTSP, the dhcpd file is located in . Any changes you want to make to booting behaviour should be made there.
By default, LTSP ships a that serves thin clients in a dynamic range (i.e. it will hand out ip addresses to anyone who asks for them) from 192.168.0.20 to 192.168.0.250. The default dhcpd.conf file looks like:
This should handle most situations.
By default, LTSP will detect an unused network interface and configure it to be 192.168.0.254. LTSP's recommended single server installation is to use a separate network interface for the thin clients. If, however, you're not using two network interfaces, or you already have an interface in the 192.168.0 range, then you might have to configure the thin client interface differently, which means you may have to adjust the accordingly.
If the network interface that you're going to connect the thin clients to has, say, a TCP/IP address of 10.0.20.254, you'll want to replace every occurrence of 192.168.0 with 10.0.20 in the file.
Always remember, you'll need to re-start the dhcp server if you make any changes. You can do this by issuing the command:
(at the command prompt.)
Adding static entries to the dhcpd.conf
Sometimes, you may need to have a certain terminal boot with a guaranteed fixed TCP/IP address every time. Say, if you're connecting a printer to the terminal, and need to make sure the print server can find it at a fixed address. To create a fixed address, use a low number in the range of 2-19, or otherwise, if you change the range statement in the .
To create a static entry, simply add the following after the "option root-path" line:
Substitude the MAC address for the mac address of the thin client you wish to fix the address of. The fixed-address will be the TCP/IP address you want, and "hostname" is the name you wish to give the host. This kind of setup is relatively complex and the admin should have a full understanding of how DHCP works before attempting such a setup. For more information, check the Internet.
DHCP failover load balancing
Another common method of load balancing is to use DHCP load balancing. There's an excellent writeup on the topic at:
= Lockdown with Sabayon (user profile manager) and
Pessulus (lockdown editor) =
A common requirement in both schools and businesses is having the ability to lock down the desktop and provide certain default configurations.
In LTSP, the applications you'll want to use are Sabayon and Pessulus. You'll want to add them from the package manager.
The Sabayon user profile editor looks like a window that contains a smaller sized picture of your desktop. Within this window, you can create a default layout: add icons to panels and the desktop, lock down the panels so they can't be modified, remove access to the command line, etc.
Once you're done, you can save your profile. You have the option of applying your profile to either individual users, or all users on the system. Please consult the manual included with Sabayon for all the details.
More information is available here:
Replication of desktop profiles
If you customize user's desktop, then custom desktop profiles should be copied to every server. Gnome desktop profiles created with Sabayon are located in
Managing the thin client
Previously, there was a program called TCM or thin client manager, which was responsible for checking what was happening on the various thin terminals, messaging between them, locking, or generally offering support from a master terminal. This has now been replaced by the use of Italc, which must be separately installed depending on your distribution.
By choosing a single user and right clicking on that users name, you will open up the context menu. From here you can choose "Lockdown", which will allow you to set options to restrict a particular user. Clicking this menu item will invoke the "Pessulus" program, which is the Gnome lockdown editor. Ticking and unticking options in Pessulus will enable and disable certain functions for that particular user. There is a padlock next to each option in Pessulus. Ticking this will make the option unchangeable by the user. This is called a mandatory setting. For further help with Pessulus, please refer to the Pessulus documentation.
Updating your LTSP chroot
At some point in the future, updates will become available for your LTSP server. You must remember that although you may have applied all the updates to the server itself, as in the instructions....HERE it is likely that the LTSP chroot will also need updating. To do this you must open up a terminal and use the following commands.
First make sure the Client environment has the same Package lists as the Server, to achieve that, you will copy the /etc/apt/sources.list (on Debian and Ubuntu) or the /etc/yum.repos.d/fedora.repo file from the Server to the Client environment.
Now issue the command below.
(replace <arch> with the architecture
you are working with.)
This will change your root directory to be the LTSP clients root directory. In essence, anything you now do inside here, will be applied to the LTSP clients root. This is a separate small set of files that are used to boot the clients into a usable, and enable them to contact the LTSP server. Once inside this shell, we must type the following command to obtain the latest list of packages from the apt/yum servers.
on Debian and Ubuntu
You need to mount in the chroot before beginning, as some of the packages you install may need resources in to install correctly.
To be sure no deamons are started do the following:
Once this has completed you will have to upgrade the software in the chroot by running the following command:
(on Debian and Ubuntu)
Just in case is still mounted when you exit the chroot, unmount it first by doing:
Once you're done, you must leave the chroot by either typing or by using the key combination Ctrl+D. This will return you to the root of the server.
If your kernel has been upgraded you must run the LTSP kernel upgrade script, to ensure that your LTSP chroot uses the latest version. This is performed by running the command below:
All of your clients will now use the latest kernel upon their next reboot.
Finally, you must remember to rebuild the NBD boot image from your chroot with the following command:
(add architecture using -arch= addition)
Be advised that this may take a few minutes, depending on the speed of your server.
Here you can find some solutions to common questions and problems.
Using NFS instead of NBD
Using NBD instead of NFS has several advantages:
Using a squashfs image we can now merge that together in a unionfs to get writeable access which is a lot faster during bootup.
A squashed root filesystem uses less network bandwidth.
Many users and administrators have asked us to eliminate NFS, for reasons of site policy. Since the squashed image is now served out by nbd-server, which is an entirely userspace program, and is started as the user nobody, this should help to eliminate concerns over NFS shares.
However, some people still want to use NFS. Fortunately, it's easy to switch back to NFS, if it's so desired:
On the server, use the chroot command to maintain the LTSP chroot:
Now edit /etc/default/ltsp-client-setup and change the value of the root_write_method variable to use bind mounts instead of unionfs, it should look like this afterwards:
Next, create the file and add the following line (set the value of the BOOT variable to nfs):
Regenerate the initramfs:
Hit CTRL-D to exit the chroot now. Make sure LTSP uses the new initramfs to boot:
Enabling dual monitors
First, I am going to start with a couple assumptions:
I will assume that you are operating thin clients with an NBD file system in this write-up.
I will assume that you are running Ubuntu 8.04.1
I will assume that you are running LTSP 5
I will assume that you are replacing a running image that has been properly tested, and is working.
Create a new image to ensure your configuration is congruent with my successfully tested configuration.
(note the --arch i386 command is required for my system because it's running an amd64 kernel. It may not be required for individuals running a 32-bit kernel)
Download the pertinent VIA unichrome driver for your chipset from this web site: Be sure to select the proper OS as well. The installation script is set up specifically for the directory structure of each OS, and will error out if the wrong OS release is installed. Next we need to move the downloaded file to the image directory
After that, we need to chroot to the same image directory.
Unpack the driver in the root directory
After unpacking, enter the directory:
Run the file contained inside to start the driver installation
(The following error: "VIAERROR:The /etc/X11/xorg.conf is
missing!" Can be ignored. We will be replacing the xorg.conf anyway, and the drivers are still installed properly.)
Next we need to put a proper xorg.conf in to the proper directory.
Now paste the following in to the empty file:
IN THE ABOVE SECTION PASTED INTO THE XORG.CONF, NOTICE THAT THERE ARE RESOLUTIONS SPECIFIED PER MONITOR. PLEASE ENSURE THAT YOU HAVE THE PROPER RESOLUTIONS FOR YOU YOUR MONITOR ENTERED ON THOSE AREAS. Be sure to save the file as xorg.conf and exit out of your chroot'd image. <CTRL+D or "exit"> next we need to put in an addendum in the lts.conf
Feel free to comment out anything that you need to in the lts.conf. I will include my full lts.conf as an example:
Feel free to copy-paste this in it's entirety if you want, but you will only need the last line. After you add the X_CONF line, save & exit. Now we need to make the changes that we have made take effect in the image
(again, the --arch i386
will not be required for most, but I am putting it in just in case a user has a x64 installation on their server.) That should do it! Boot up the client and you should be good to go.