Red Hat Certified System Administrator & Engineer

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1 Red Hat Certified System Administrator & Engineer Exams EX200 and EX300 Red Hat Enterprise Linux 6 Training Guide & A Quick Deskside Reference December 2012 Asghar Ghori 1246 Heil Quaker Blvd., La Vergne, TN USA Chapter House, Pitfield, Kiln Farm, Milton Keynes, UK MK11-3LW

2 Technical Reviewers: Syed R. Ali, Kurt Glasgow, Oleg Waisberg, and Mehmood Khan Editors: Masood Pehlvi and Joan Weytze Cover Design: Wajahat Syed Printers and Distributors: Lightning Source Inc. Copyright 2012 Asghar Ghori All rights reserved. No portion of this book may be stored in a retrieval system, transmitted, or reproduced in any form, including but not limited to photocopying or other recording, without the express written consent of the author. Printed in the USA, UK, France, Germany, Italy, Spain, and Australia. ISBN: Library of Congress Control Number: Printed and Distributed by: Lightning Source Inc. To order in bulk at special quantity discounts for sales promotions or for use in training programs, please contact the author at asghar_ghori2002@yahoo.com 2012, Red Hat, Inc. Images Printed with Permission. Red Hat is a registered trademark of Red Hat, Inc. in the U.S. and other countries. RHCSA and RHCE are registered trademarks of Red Hat, Inc. in the U.S. and other countries. Linux is a registered trademark of Linus Torvalds in the U.S. and other countries. UNIX is a registered trademark of The Open Group in the U.S. and other countries. Microsoft and Windows are US registered trademarks of Microsoft Corporation. Intel is the trademark or registered trademark of Intel Corporation or its subsidiaries in the United States and other countries. The author has made his best efforts to prepare this book. The contents are based on Red Hat Enterprise Linux version 6. The author makes no representation or warranties of any kind with regard to the completeness or accuracy of the contents herein and accepts no liability whatsoever including but not limited to merchantability, fitness for any particular purpose, or any losses or damages of any kind caused or allegedly caused directly or indirectly from this material. This book is not a replacement for RHCSA /RHCE training courses offered by Red Hat, Inc., however, it may be used to prepare for the Red Hat Certified System Administrator (RHCSA) and the Red Hat Certified Engineer (RHCE) exams based on Red Hat Enterprise Linux version 6. Neither author nor publisher warrants that use of this publication will ensure passing the relevant exams or that the information contained herein is endorsed by Red Hat, Inc. ii

3 Preface Red Hat s EX200 and EX300 exams are performance-based and touch a wide array of topics. The exams present configuration scenarios to be accomplished on live systems within an allotted time frame. This book provides a single, comprehensive resource that equips readers with enough knowledge to comfortably pass both exams. At the same time, this book presents procedures to help configure and administer a Red Hat Enterprise Linux (RHEL) 6 computing environment effectively and efficiently. Throughout this book, step-by-step implementation procedures have been furnished. My suggestions to you are to study the material thoroughly; perform the full installation, configuration, and administration tasks provided; perform all exercises diligently; answer all questions presented at the end of each chapter; attempt all lab exercises offered at the end of each chapter; and then attempt the sample exam exercises presented in the appendix. While you study the book, have one 64-bit laptop or desktop computer with at least one dual-core processor, 4GB of memory, and builtin support for hardware virtualization available for implementing practice exercises and labs. I would recommend that you purchase a subscription for RHEL6 for one of the systems so as to have access to the software repository and benefits offered by the Red Hat Network. Alternatively, you can download a free copy of either CentOS or Scientific Linux, which are non-commercial versions of RHEL and are 100% compatible with it. While performing exercises and labs, if a command does not produce desired results, see what message it generates and try to resolve it. Minor issues, such as a wrong path, prevent commands from being executed. Sometimes, there are syntax errors in the command construct. You might need to adjust settings presented in exercises to make them work on your systems. If the exercises do not produce the expected results, check settings on your computer, modify what is not working and see if the modifications that you have made work. RHEL manual pages prove helpful and useful in comprehending commands and their syntax. There are numerous commands, command options, service daemons, and configuration, log, and startup/shutdown files in the operating system; discussing all of them is not possible within the scope of this book. There are four areas where you should be focusing on in order to gain expertise with RHEL (CentOS or Scientific Linux for that matter), as well as preparing yourself for the exams: 1) grasping concepts; 2) mastering implementation procedures, exercises, and labs; 3) learning commands, configuration files, and service daemons; and 4) being able to troubleshoot and resolve problems. An excellent understanding of which command involves which options and updates which files, which daemon provides what services, etc. should also be developed. This way you will have a better overall understanding of what exactly happens in the background when a command is executed. This book provides all that knowledge. Troubleshooting becomes easier when concepts are clear and working knowledge is solid. I am maintaining the website where errors encountered in the book, additional exam information, and links to useful resources are made available. I encourage you to visit this website. At the end, I would like to ask you to forward your constructive feedback to my personal address asghar_ghori2002@yahoo.com about the content, structure, layout, consistency, clarity, and flow of the book. Please also let me know if you come across any errors or mistakes. Improvement is a continuous process and I am sure your feedback will help me publish a better and improved next edition. Good luck in your endeavors. Asghar Ghori December 2012 Toronto, Canada iii

4 Acknowledgments I am grateful to God who enabled me to write this book successfully. I would like to thank my friends, colleagues, students, and peers who supported and encouraged me throughout the lifecycle of writing this book. I am grateful to all of them for their invariable support, constant encouragement, constructive feedback, and valuable assistance. I would like to pay special thanks to my wife, two daughters, and two sons, who endured me while I was away from them hiding in my basement and working on this project. This work could not have been accomplished without the assistance, support, and love that they had demonstrated. Finally, I would like to pay my best regards to my mother and my deceased father. Asghar Ghori iv

5 About the Author Currently working as a consultant, Asghar Ghori has been in the IT industry for 22 years. He started his career as a UNIX support engineer working with SCO UNIX and SCO XENIX, visiting customers and providing UNIX technical support services. He has worked with several flavors of the UNIX operating system including HP-UX, Oracle Solaris, and IBM AIX, as well as Red Hat Enterprise Linux and a few other Linux distributions. He has worked in support and administration, and as technical lead, solution design lead, and consultant serving business and government customers. In addition, he has architected and deployed solutions involving clustered servers and tiered storage that span data centers around the world. Asghar has been involved in planning, developing, and executing disaster recovery procedures for many enterprises. Asghar holds a BS in Engineering, and has delivered and attended numerous training programs. He has been delivering courses on UNIX & Linux for the past eleven years at local colleges in Toronto, Canada. He is Red Hat Certified System Administrator (RHCSA), HP Certified Systems Administrator, HP Certified Systems Engineer, SUN Certified System Administrator (SCSA), IBM Certified Specialist for AIX, Certified Novell Engineer (CNE), and holds the Project Management Professional (PMP) certification designation. v

6 Conventions Used in this Book The following typographic and other conventions are used throughout this book: Book Antiqua Italic is used in text paragraphs for special words or phrases that are emphasized. For example: Linux, like all UNIX operating systems, is a multi-user, multi-tasking, multi-processing and multi-threading operating system. This means that.. Times Roman Italic is used in text paragraphs and Tables to highlight file and directory names, commands, daemons, hostnames, usernames, and URLs. For example: To go directly from /etc into a sub-directory dir1 under aghori s home.. Times Roman Bold is used to highlight commands and command line arguments that the user is expected to type at the command prompt. For example: $ ls lt All headings and sub-headings are in California FB font, and are bolded. Ctrl+x key sequence implies that you hold down the Ctrl key on the keyboard and then press the other key. Courier New font is used for such sequences, as well as it is used to highlight keyboard keys such as Enter, Esc, and so on. Andalus 9 is used to segregate command output, shell script contents, and information expected to be entered in configuration files from the surrounding text Dotted lines show the continuation in command output. Indicates additional information. Indicates a task performed using a RHEL graphical tool. vi

7 About the RHCSA and RHCE Exams The Red Hat Certified System Administrator (RHCSA ) and the Red Hat Certified Engineer (RHCE ) certification exams are performance-based, hands-on practical exams designed for IT professionals. These exams are presented in electronic format. During the exams, the candidates do not have access to the Internet or other printed or electronic documentation except for what comes standard with the RHEL6 operating system software. The official exam objectives are listed at for RHCSA and that for RHCE at Visit the URLs for up-to-date and more in-depth information. The exam objectives are covered in sufficient detail in the chapters throughout this book. A list of the exam objectives is presented below along with chapter numbers where the objectives are discussed. RHCSA Specific Skills: Understand and Use Essential Tools: 1. Access a shell prompt and issue commands with correct syntax (chapter 2) 2. Use input-output redirection (>, >>,, 2>, etc) (chapter 4) 3. Use grep and regular expressions to analyze text (chapter 3) 4. Access remote systems using ssh and VNC (chapter 2) 5. Log in and switch users in multiuser run levels (chapter 11) 6. Archive, compress, unpack, and uncompress files using tar, star, gzip, and bzip2 (chapter 2) 7. Create and edit text files (chapter 4) 8. Create, delete, copy, and move files and directories (chapter 3) 9. Create hard and soft links (chapter 3) 10. List, set, and change standard ugo/rwx permissions (chapter 4) 11. Locate, read, and use system documentation including man, info, and files in /usr/share/doc (chapter 2) Operate Running Systems 12. Boot, reboot, and shut down a system normally (chapter 8) 13. Boot systems into different runlevels manually (chapter 8) 14. Use single-user mode to gain access to a system (chapter 8) 15. Identify CPU/memory intensive processes, adjust process priority with renice, and kill processes (chapter 5) 16. Locate and interpret system log files (chapter 8) 17. Access a virtual machine's console (chapter 7) 18. Start and stop virtual machines (chapter 7) 19. Start, stop, and check the status of network services (chapter 8) Configure Local Storage 20. List, create, delete, and set partition type for primary, extended, and logical partitions (chapter 9) 21. Create and remove physical volumes, assign physical volumes to volume groups, and create and delete logical volumes (chapter 9) 22. Create and configure LUKS-encrypted partitions and logical volumes to prompt for password and mount a decrypted file system at boot (chapter 10) 23. Configure systems to mount file systems at boot by Universally Unique ID (UUID) or label (chapter 10) 24. Add new partitions and logical volumes, and swap to a system non-destructively (chapters 9 and 10) vii

8 Create and Configure File Systems 25. Create, mount, unmount, and use ext2, ext3, and ext4 file systems (chapter 10) 26. Mount, unmount, and use LUKS-encrypted file systems (chapter 10) 27. Mount and unmount CIFS and NFS network file systems (chapters 10, 19, and 20) 28. Configure systems to mount ext4, LUKS-encrypted, and network file systems automatically (chapter 10) 29. Extend existing unencrypted ext4-formatted logical volumes (chapter 9) 30. Create and configure set-gid directories for collaboration (chapter 4) 31. Create and manage Access Control Lists (ACLs) (chapter 10) 32. Diagnose and correct file permission problems (chapter 4) Deploy, Configure, and Maintain Systems 33. Configure networking and hostname resolution statically or dynamically (chapter 13) 34. Schedule tasks using cron (chapter 5) 35. Configure systems to boot into a specific runlevel automatically (chapter 8) 36. Install Red Hat Enterprise Linux automatically using Kickstart (chapter 7) 37. Configure a physical machine to host virtual guests (chapter 7) 38. Install Red Hat Enterprise Linux systems as virtual guests (chapter 7) 39. Configure systems to launch virtual machines at boot (chapter 7) 40. Configure network services to start automatically at boot (chapter 8) 41. Configure a system to run a default configuration HTTP server (chapter 7) 42. Configure a system to run a default configuration FTP server (chapter 7) 43. Install and update software packages from Red Hat Network, a remote repository, or from the local file system (chapter 6) 44. Update the kernel package appropriately to ensure a bootable system (chapter 8) 45. Modify the system bootloader (chapter 8) Manage Users and Groups 46. Create, delete, and modify local user accounts (chapter 11) 47. Change passwords and adjust password aging for local user accounts (chapter 11) 48. Create, delete, and modify local groups and group memberships (chapter 11) 49. Configure a system to use an existing LDAP directory service for user and group information (chapter 13) Manage Security 50. Configure firewall settings using system-config-firewall or iptables (chapter 12) 51. Set enforcing and permissive modes for SELinux (chapter 12) 52. List and identify SELinux file and process context (chapter 12) 53. Restore default file contexts (chapter 12) 54. Use boolean settings to modify system SELinux settings (chapter 12) 55. Diagnose and address routine SELinux policy violations (chapter 12) viii

9 RHCE Specific Skills: System Configuration and Management 56. Route IP traffic and create static routes (chapter 16) 57. Use iptables to implement packet filtering & configure network address translation (NAT) (chapter 15) 58. Use /proc/sys and sysctl to modify and set kernel runtime parameters (chapter 17) 59. Configure a system to authenticate using Kerberos (chapter 16) 60. Build a simple RPM that packages a single file (chapter 14) 61. Configure a system as an iscsi initiator that persistently mounts an iscsi target (chapter 14) 62. Produce and deliver reports on system utilization (processor, memory, disk, and network) (chapter 15) 63. Use shell scripting to automate system maintenance tasks (chapter 14) 64. Configure a system to log to a remote system (chapter 15) 65. Configure a system to accept logging from a remote system (chapter 15) Network Services Network services are an important subset of the exam objectives. RHCE candidates should be capable of meeting the following objectives for each of the network services listed below: Install the packages needed to provide the service Configure SELinux to support the service Configure the service to start when the system is booted Configure the service for basic operation Configure host-based and user-based security for the service HTTP/HTTPS (chapter 21) Configure a virtual host Configure private directories Deploy a basic CGI application Configure group-managed content DNS (chapter 16) Configure a caching-only name server Configure a caching-only name server to forward DNS queries FTP (chapter 20) Configure anonymous-only download NFS (chapter 19) Provide network shares to specific clients Provide network shares suitable for group collaboration SMB (chapter 20) Provide network shares to specific clients Provide network shares suitable for group collaboration SMTP (chapter 18) Configure a mail transfer agent (MTA) to accept inbound from other systems Configure an MTA to forward (relay) through a smart host SSH (chapter 21) Configure key-based authentication Configure additional options described in documentation NTP (chapter 17) Synchronize time using other NTP peers ix

10 Suggestions When Taking the Exams 1. Save time wherever possible as time is of the essence during the exams. Perform tasks using either text or graphical tools, whichever you feel more comfortable with. Install a graphical tool if you need it and if it is not already loaded. 2. Make certain that any changes that you have made must survive across system reboots. 3. Use any text editor that you feel comfortable with to modify text files. 4. Inform the exam proctor right away if you identify a hardware issue with your system. 5. Exams are administered with books closed and no access to the Internet and electronic devices. 6. Read each exam task carefully and understand it thoroughly before attempting it. Exam Fees and How to Register The fee for either the RHCSA or the RHCE exam is US$400. To register for an exam, visit or and click ENROLL TODAY to enroll online. Note that the exams are administered on Fridays only. The RHCSA exam begins at 9am and the RHCE exam at 2pm. x

SysadminSG RHCSA Study Guide

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