A DOS® Server In a Virtual Machine
The Red Hat Exams
- Chapter 1: Prepare for Red Hat Hands-on Certifications
The Red Hat exams are an advanced challenge. While this book covers the Red Hat Certified System Administrator (RHCSA) exam, it provides the foundation for those who want to earn the Red Hat Certified Engineer (RHCE) certification. Red Hat offers several courses to help prepare for these exams, as described in the front matter and in this chapter.
- Chapter 2: Virtual Machines and Automated Installations
Even though installation is specified as a requirement in the RHCSA objectives, Red Hat has also stated that their exams are now given on pre-installed systems. In other words, you won't have to install RHEL 6 on a bare-metal system during the exams. However, the management of virtual machines (VMs) and Kickstart installations are also required RHCSA skills. In other words, you need to be prepared to install RHEL 6 on a VM over a network, manually, and with the help of Kickstart.
- Chapter 3: Fundamental Command Line Skills
The Red Hat exams are an advanced challenge. This chapter covers RHCSA requirements that were formerly listed as prerequisites for the now-obsolete RHCT certification. Many of these requirements specify basic command line tools associated with entry-level certifications such as those offered by the Linux Professional Institute.
- Chapter 4: RHCSA-Level Security Options
Linux security starts with a concept known as "discretionary access controls". They include the permissions and ownership associated with files and directories. Default permissions on new files depend on the umask. Permissions can go further with specialized bits. Linux discretionary access controls can be configured on a more fine-grained basis with the help of access control lists (ACLs). Those ACLs support permissions given to specific users, overriding standard ownership and permissions.
- Chapter 5: The Boot Process
This chapter is focused on what happens from the moment a system is powered up to the time a login prompt is available. Those are the fundamentals of the boot process. When RHEL 6 is properly installed, the BIOS/UEFI points to a specific media device. Assuming it's a local hard drive, the master boot record (MBR) of that device points to the GRUB bootloader. Once an option to boot RHEL 6 is selected in GRUB, the associated commands point to and initialize the Linux kernel, which then starts init, the first Linux process. The init process then initializes the system and moves into appropriate runlevels. When Linux boots into a specific runlevel, it starts a series of services, including the client associated with the Network Time Protocol (NTP). You can customize this process.
- Chapter 6: Linux Filesystem Administration
Linux installation is easy, at least for anyone serious about Red Hat certification. Most administrators have to maintain existing systems. Critical skills related to filesystems include adding new partitions, creating logical volumes, setting up volume encryption, and more. In many cases, you'll want to make sure these filesystems are mounted automatically during the boot process, and that requires a detailed knowledge of the /etc/fstab configuration file.
- Chapter 7: Package Management
After installation is complete, after systems are secured, filesystems are administered, and more, you still have work to do. To customize the system as needed, you may need to add or remove packages, among other tasks. To make sure the right updates are installed, you need to know how to get a system working with the Red Hat Network (RHN) or the repository associated with a rebuild distribution.
- Chapter 8: User Administration
Fundamental to the tasks associated with Linux administration is the management of users and groups. In this chapter, you'll examine different ways to manage the variety of users and groups available to Linux. Important skills in this area range from the simple login to user account management, group membership, group collaboration, and network authentication. The configuration of administrative privileges for Linux users can help the master administrator distribute responsibilities to others.
- Chapter 9: RHCSA-Level System Administration Tasks
As the final chapter related to the RHCSA exam, this covers those functional system administration tasks not already covered in other chapters. One part of remote access not already covered is based on the GUI-based sharing enabled through Virtual Network Computing (VNC).
- Chapter 10: A Security Primer
As you start the first chapter of the RHCE section of this book, you'll start with security. Many administrators and enterprises move toward Linux because they believe it's more secure. Since most Linux software is released under open-source licenses, the source code is available to all. Some believe that provides advantages for crackers who want to break into a system.
- Chapter 11: System Services and SELinux
This is a "big picture" chapter with respect to the RHCE objectives. Those objectives are focused on common tasks that you'll perform on the job. These tasks relate to the detailed configuration of RHCE-level services.
- Chapter 12: RHCE Administrative Tasks
The automation of system maintenance is an objective for both the RHCSA and RHCE exams. For the RHCE, you need to know how to create a shell script for that purpose. You'll study some example scripts used on RHEL 6. Standard scripts may be used on an hourly, daily, or even weekly basis. The Linux kernel is flexible and highly customizable. With different run-time parameters configured in the /proc directory, kernels can be modified to meet the needs of your users.
- Chapter 13: Electronic Mail Servers
Linux offers a number of alternative methods for handling incoming and outgoing e-mail. RHEL 6 includes sendmail and Postfix for this purpose. Yes, it includes Dovecot, Fetchmail, and Procmail as well, but since the RHCE objectives focus on services associated with the Simple Mail Transfer Protocol (SMTP), this chapter focuses on sendmail and Postfix, as they are the two supported services associated with SMTP.
- Chapter 14: The Apache Web Server
Unix was developed by AT&T in the late 1960s and early 1970s, and it was freely distributed among a number of major universities during those years. When AT&T started charging for Unix, a number of university developers tried to create clones of this operating system. One of these clones, Linux, was developed and released in the early 1990s.
- Chapter 15: The Samba File Server
Samba is the Linux implementation of the networking protocols used to connect Microsoft operating systems. Microsoft networking is based on the Common Internet File System (CIFS), which was developed from the Server Message Block (SMB) protocol. Samba was developed as a freely available SMB server for all Unix-related operating systems, including Linux, and has been upgraded to support CIFS.
- Chapter 16: More File-Sharing Services
Linux is designed for networking. Besides Samba, covered in Chapter 15, there are two other major services associated with sharing files on a network: NFS and FTP. RHEL 6 does not include GUI tools for these services. Even if Red Hat did as such, it's fastest to learn to configure these services from the command line. If you know these services, you can do more in less time by directly editing key configuration files.
- Chapter 17: Administrative Services: DNS, FTP, and Logging
This chapter examines four administrative services: the Domain Name System (DNS), system activity reports, system logging services, and the Network Time Protocol (NTP) service. That's less complex than it sounds. As for DNS, the RHCE objectives require only the configuration of a caching-only nameserver that may forward queries. So this book does not cover the configuration of a master or secondary DNS server.
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