Certification Objective 2.09-Installation Validation

RHEL creates a number of files during the installation process. These files essentially document what happened. The basic installation log file, /root/install.log, lists the packages that Anaconda installed on your system. The commands used by Anaconda to install Linux are stored in the /root/anaconda-ks.cfg file. This can serve as a template for the kickstart process, which you can use to install RHEL automatically on different computers. I describe this process in more detail in Chapter 5.

The Installation Log File

The installation log file, /root/install.log, provides a baseline. After you run Linux for some time, you'll probably have installed and upgraded a number of additional packages. You can refer back to this file to find the packages installed when Linux was installed on this computer.

Installation Troubleshooting

Installation involves many running processes and many parts. The system logs everything to an installation log file and separates related information among four of the five virtual console screens supported during the installation.

Exam Watch

If your installation is trouble-free, you'll have a few minutes on your hands during the Installation part of the exam. Use that time to plan how you'll configure the services per the requirements of your particular exam. But pay attention to the following sections. If your installation gets stuck, the console screens described can quickly help you diagnose the problem.

The Console Installation Output Screens

Six consoles are available during the installation process, and each tells a different story. What you see depends on whether you install in text or graphical mode. A network graphical installation is something of a hybrid; it starts in text mode before connecting to the network source and proceeding to the graphical installation.

Text mode starts in the first virtual console. Graphical mode runs in the sixth virtual console (it used to be the seventh console). You can switch between virtual consoles using the commands defined in Table 2-3. If you're in text mode, you don't need to use the CTRL key (but it does no harm). As you can see in the table, each console is associated with a function key.

Table 2-3: Installation Virtual Console Commands and Functions

Command	Console and Function
CTRL-ALT-F1	Text installation display; if you're running in graphical mode, it includes the basic commands to start graphics drivers.
CTRL-ALT-F2	Accesses a bash shell prompt; available after the first few installation steps.
CTRL-ALT-F3	Lists the log of installation messages; if network problems occur, you may see related messages here.
CTRL-ALT-F4	Displays all kernel messages, including detected hardware and drivers.
CTRL-ALT-F5	Installation displays partition formatting; nothing is shown here until Anaconda formats the actual partitions.
CTRL-ALT-F6	Graphical installation display; active only if you're running the installation program in graphical mode (was formerly available from CTRL-ALT-F7). Naturally, if you're installing in text mode, nothing is shown in this console.

The messages on the third and fourth consoles can scroll by quickly; fortunately they're collected in dedicated files, which are described shortly.

Installation Bash

You can find a bash shell on the second console, which can help you review what has been installed so far. Check it out for yourself with the CTRL-ALT-F2 command. You'll see the following installation boot prompt during the installation process:

 sh-3.1# 

This prompt allows you to run standard bash commands on the system as configured so far. Before Anaconda starts installing packages, you can inspect a number of things at this prompt. The installation files from the CD or network source will be mounted on the /mnt/source directory. You can also find a number of interesting files in the /tmp directory; the significant ones are described in Table 2-4.

Table 2-4: /tmp Directory Configuration Files During the Installation Process

File from Installation /tmp	Description
anaconda.log	Contains a log of installation messages (from the third console).
ks.cfg	If you're installing from a kickstart configuration file, it's stored in the /tmp directory; otherwise, this doesn't exist.
modprobe.conf	Includes detected hardware that requires a driver module (frequently includes network cards).
netinfo	Contains IP address information for configured network cards; if no cards are configured (e.g., during a local installation, this file does not exist).
syslog	Includes a log of kernel messages (from the fourth console).
XConfig.test	Contains a temporary X Window configuration file.

On the Job 

The files listed in this section are deleted or moved after installation is complete.

Other Consoles

The third console primarily lists detected hardware. If your computer is having problems with something critical such as the CD drive or network card, you'll see it here.

The fourth console tells you more about detected hardware. However, you may need to be a detective to understand these messages. For example, you might see the following message:

 <6>pcnet32: 1 cards_found. 

You might not know there's a problem unless you remember that two network cards are on this computer.

On the fifth console, you can see what happens to your partitions; it lists the output of the mke2fs command, which can tell you if there's a problem with your partitions. This console will be empty until Anaconda starts formatting partitions.

While Installing Software

Once Anaconda starts installing software, you'll see the Installing Packages screen, where you can watch as it actually installs Linux on your computer. Once this process starts, press CTRL-ALT-F2 to return to the bash console. Then run the following command:

 sh-3.1# cd /mnt/sysimage 

You can browse around the directory tree as it's being built. Even better, once enough packages are installed, you can change the root directory to /mnt/sysimage with the following command:

 # chroot /mnt/sysimage 

You can return to the installation console with the exit command.