THL 5

Building TarHeel Linux on Your Machine

Download the TarHeel Linux 5.x NetInstall iso image from the “Installation” page.  Burn a disc with the iso image to become the Tarheel Linux NetInstall 5.x disc.

Insert the TarHeel Linux NetInstall CDROM in the drive. If you machine has two drives, use the uppermost, as that is generally the only one the BIOS will see as a boot option.

Power cycle the machine.

As soon as you see the Lenovo ThinkCentre splash screen, tap the F12 key. Once is good, twice is often better. This will cause the BIOS boot menu to be displayed. Use the arrow keys to choose the cdrom drive (look for CD or CD/DVD – this will vary), and hit the “Enter” key.

There will be a pause at a TarHeel Linux splash screen with a “boot:” prompt at the bottom.

IMPORTANT: This build will reformat your hard drive. If this is not what you intended, remove the cdrom NOW. If you wish to continue with your TarHeel Linux build, all you need to do is hit the “Enter” key.

Now, it’s time for the TarHeel Linux kickstart server to do the work. You can go get a cup of coffee, although friendly and helpful messages will come up now and again to help you pass the time. If you are really interested in what software is being loaded, all the packages are listed with short descriptions as they are loaded.

Once the load is complete, follow the instructions on the screen to remove the TarHeel Linux cdrom and then click on the “Reboot” button in the lower right.

Just before the reboot completes, you will be asked for the ONYEN of the person who will hold root on this machine. Next, you will be prompted for the new root password. If the primary user of this machine is different from the person who holds root, you will be prompted for that ONYEN as well. These accounts will be added immediately.

Next, the process will look back to the repositories and completely update the system. Depending on the speed of the network connection and the load on the machine holding the repository, this can take between 5 and 15 minutes. Now the machine reboot will put the latest kernel update in place.

When this boot is complete, you will have your very own TarHeel Linux host. Congratulations!

Terminal Window

A right-click of your mouse anywhere on the wallpaper will display a menu which will enable you to open a terminal window. In that window, choose Edit/Profiles…/Default/[Edit]. The General menu allows you to choose a font size – which is probably the easiest way to control the actual size of your window. Check out the Color menu to choose background and font colors you like. Under the Effects menu, you can add transparency to the terminal background.

Cool Stuff: On the uppermost bar, you can change the screensaver: click on System/Preferences/Screensaver. We’ve added a couple of extras for your amusement. If you have a collection of photos you would like to use instead, park them in your ~/Pictures folder, and choose Pictures from the menu. In a similar way, if you’ve seen more of the machine room cabling than you can deal with, you can change the wallpaper (aka Desktop Background) to one of your favorite images. That exercise is left to the user.

IMPORTANT: It is a very Bad Idea to log into a Linux machine directly as root. Always log in as yourself and then use the following command to create a root shell:

prompt%  su -

The “minus” will create a shell with root’s complete environment – including having the various sbin directories in the PATH. This action gets properly logged – in the case that you would ever want to know if anyone else tried to do something as root. The person who holds the root password can also use the sudo command to easily run single commands as root without needing to invoke a root shell. This means that you must protect your own password every bit as carefully as you protect the root password!

Adding New Users

We have an adduser program which will take an ONYEN as an argument, or the name of a file with a list of ONYENS, and will create accounts for those people on your machine using the correct NumericUID, NumericGID, and shell information from the UNC LDAP server for complete compatibility across systems. By default, home directories are created in /home. However, you can also specify the location of the home directories – even if they will reside on a remote server. You will need to be root to run this program. It is called “adduser_unc” and lives in /usr/local/sbin:

# adduser_unc  chen

or

# adduser_unc  -f /path/to/onyenfile

The format of this file is as follows:

# cat /path/to/onyenfile
chen
aarnold
bpack1
dwatson

For home directories exported from remote hosts:

# adduser_unc  -h /mnt/remote/home  onyen

The administrator of the remote machine will have to create the actual home directories and make sure that the NumericUID and NumericGIDs match. If you have skel files you want each user to start with, you must give copies to this administrator. The default is to use the “dot” files in /etc/skel on your TarHeel Linux machine. You will have to put the proper entry in /etc/fstab and create a mount point to make sure this remote volume is properly mounted.

 

Running Applications on Remote Hosts

Sometimes, you will find that you need a bigger hammer, or possibly – more hammers. In addition to the many applications available to you on your TarHeel Linux machine, ITS Research Computing is able to offer you even more options! The following is an example of launching a job to run on our research cluster, Emerald. This is done by opening a terminal window on your TarHeel Linux machine, and connecting to Emerald in a way which enables X11 forwarding:

prompt% ssh -X emerald.isis.unc.edu

The following will display the GUI for the grace application locally on your TarHeel Linux machine, but run the application on the Emerald cluster:

emerald% bsub -q int -Ip /afs/isis/pkg/grace/bin/xmgrace

Alternatively, some of the more popular applications are already set up to use our Load Sharing Facility (that’s what bsub is all about).

emerald% xmatlab

Both of these examples will bring up the GUI for the respective application on your local machine.

IMPORTANT: Using the Load Sharing Facility accomplishes two things. First, it will put your job in the correct queue so that it will complete quickly without needing to compete with larger, longer, or more numerous jobs submitted by other users. Second, it will run your job on a compute node rather than a login node. Compute nodes are tuned to compute – login nodes are not. Running an application directly from the Emerald prompt causes it to run on the login node, which causes other users to have difficulty connecting to the cluster, which causes one of our system administrators to get in touch with you. Our systems administrators are very nice people, but if you want to get their attention, please use email or the phone.