Two-Minute Drill | Linux Patch Management: Keeping Linux Systems Up To Date

Here are some of the key points from the certification objectives in Chapter 16. Troubleshooting Strategies

❑	During the Troubleshooting and System Maintenance exam, use your experience. You may have seen the problem before.
❑	If you aren't sure about a problem, try the simplest solution first. q If all else fails, use the scientific method.
❑	Know how to boot Linux into different runlevels; it can help you bypass many problems and boot a system.
❑	RHCE candidates should also know how to boot Linux from the first installation CD, using linux rescue mode.

❑	Misconfigured networking can be diagnosed with key commands such as ifconfig and ping. It can be corrected in related configuration files or with the Red Hat Network Configuration tool.
❑	Misconfigured hostname resolution problems relate to connections to /etc/ hosts or DNS servers.
❑	Configure the X Window System using the Red Hat Display Configuration tool, commands such as Xorg -configure, or by directly editing /etc/X11/xorg.conf.
❑	Configure a desktop environment and login manager with key configuration files such as /etc/X11/prefdm and /etc/X11/xinit/xinitrc.

❑	Knowing how to diagnose and correct boot failures means knowing the GRUB configuration file and command line.
❑	Understand how to manage boot modules with the correct initial RAM disk.
❑	If there are filesystem errors, they may show up during the boot process and require that you use commands such as fsck to diagnose and solve them.
❑	Adding, removing, and resizing LVs require skills described in detail in Chapter 8.
❑	Know how to diagnose and solve service issues as described throughout this book.
❑	Use the Setroubleshoot browser to diagnose network service problems related to SELinux.