companies that use code from their projects. Amazingly, many open source projects support one or two developers and run exclusively on donations.
● Boxed sets, mugs, and T-shirts– Some open source projects have online stores where you can buy boxed sets (some people still like physical DVDs and hard copies of documentation) and a variety of mugs, T-shirts, mouse pads, and other items. If you really love a project, for goodness sake, buy a T-shirt!
This is in no way an exhaustive list, because more creative ways are being invented every day to support those who create open source software. Remember that many people have become contributors to and maintainers of open source software because they needed or wanted the software themselves. The contributions they make for free are worth the return they get from others who do the same.
Becoming Red Hat certified
Although this book is not focused on becoming certified in Linux, it touches on the activities you need to be able to master to pass popular Linux certification exams. In particular, most of what is covered in the Red Hat Certified Engineer (RHCE) and Red Hat Certified System Administrator (RHCSA) exams for Red Hat Enterprise Linux 7 is described in this book.
If you are looking for a job as a Linux IT professional, often RHCSA or RHCE certification is listed as a requirement or at least a preference for employers. The RHCSA exam (EX200) provides the basic certification, covering such topics as configuring disks and filesystems, adding users, setting up a simple web and FTP server, and adding swap space. The RHCE exam (EX300) tests for more advanced server configuration, as well an advanced knowledge of security features, such as SELinux and firewalls.
Those of us who have taught RHCE/RHCSA courses and given exams (as I did for three years) are not allowed to tell you exactly what is on the exam. However, Red Hat gives an overview of how the exams work, as well as a list of topics you can expect to see covered in the exam. You can find those exam objectives on the following sites:
● RHCSA—http://www.redhat.com/en/services/training/ex200-red-hat-certified-system-administrator-rhcsa-exam
● RHCE—http://www.redhat.com/en/services/training/ex300-red-hat-certified-engineer-rhce-exam
As the exam objectives state, the RHCSA and RHCE exams are performance-based, which means that you are given tasks to do and you must perform those tasks on an actual Red Hat Enterprise Linux system, as you would on the job. You are graded on how well you obtained the results of those tasks.
If you plan to take the exams, check back to the exam objectives pages often, because they change from time to time. Keep in mind also that the RHCSA is a standalone certification; however, you must pass the RHCSA and the RHCE exams to get an RHCE certification. Often, the two exams are given on the same day.
You can sign up for RHCSA and RHCE training and exams at http://training.redhat.com. Training and exams are given at major cities all over the United States and around the world. The skills you need to complete these exams are described in the following sections.
RHCSA topics
As noted earlier, RHCSA exam topics cover basic system administration skills. These are the current topics listed for Red Hat Enterprise Linux 7 at the RHCSA exam objectives site (again, check the exam objectives site in case they change) and where in this book you can learn about them:
● Understand essential tools– You are expected to have a working knowledge of the command shell (bash), including how to use proper command syntax and do input/output redirection (< > »). You need to know how to log in to remote and local systems. Expect to have to create, edit, move, copy, link, delete, and change permission and ownership on files. Likewise, you should know how to look up information on man pages and /usr/share/doc. Most of these topics are covered in Chapters 3 and 4 in this book. Chapter 5 describes how to edit and find files.
● Operate running systems– In this category, you must understand the Linux boot process, go into single-user mode, shut down, reboot, and change to different targets (previously called runlevels). You need to identify processes and change nice values or kill processes as requested. You must be able to start and stop virtual machines and network services, as well as find and interpret log files. Chapter 15 describes how to change targets and runlevels and manage system services. See Chapter 6 for information on managing and changing processes. Chapter 26 describes how to manage virtual machines. Logging is described in Chapter 13.
● Configure local storage– Setting up disk partitions includes creating physical volumes and configuring them to be used for Logical Volume Management (LVM) or encryption (LUKS). You should also be able to set up those partitions as filesystems or swap space that can be mounted or enabled at boot time. Disk partitioning and LVM are covered in Chapter 12. LUKS and other encryption topics are described in Chapter 23.
● Create and configure filesystems– Create and automatically mount different kinds of filesystems, including regular Linux filesystems (ext2, ext3, or ext4), LUKS-encrypted filesystems, and network filesystems (NFS and CIFS). Create collaborative directories using the set group ID bit feature and Access Control Lists (ACL). You must also be able to use LVM to extend the size of a logical volume. Filesystem topics are covered in Chapter 12. See Chapter 19 for CIFS and Chapter 20 for NFS coverage.
● Deploy, configure, and maintain systems– This covers a range of topics, including configuring networking, creating cron tasks, setting the default runlevel, and installing RHEL systems. You must also be able to configure a simple HTTP and FTP server. For software packages, you must be able to install packages from Red Hat Network, a remote repository, or the local filesystem. Finally, you must be able to properly install a new kernel and choose that or some other kernel to boot up when the system starts. The cron facility is described in Chapter 13. Web server (HTTP) and FTP server setups are covered in Chapters 17 and 18, respectively.
● Manage users and groups– You must know how to add, delete, and change user and group accounts. Another topic you should know is password aging, using the chage command. You must also know how to configure a system to authenticate by connecting to an LDAP directory server. See Chapter 11 for information on configuring users and groups.
● Manage security– You must have a basic understanding of how to set up a firewall (firewalld, system-config-firewall or iptables) and how to use SELinux. You must be able to set up SSH to do key-based authentication. Learn about SELinux in Chapter 24. Firewalls are covered in Chapter 25. Chapter 13 includes a description of key-based authentication.
Most of these topics are covered in this book. Refer to Red Hat documentation (https://access.redhat.com/documentation/)