Linux System Administration: Solve Real-life Linux Problems Quickly

Linux System Administration......Page 1 Table of Contents......Page 6 Preface......Page 10 How This Book Is Organized......Page 11 Conventions Used in This Book......Page 12 How to Contact Us......Page 13 Acknowledgments......Page 14 Requirements for a Linux System Administrator......Page 16 How Can We Help?......Page 17 Do You Need a Book?......Page 18 Help Wanted......Page 19 Analyzing Skill Sets......Page 20 What System Managers Should Know About Linux......Page 21 What’s Next......Page 22 Setting Up a Linux Multifunction Server......Page 23 Server Requirements......Page 24 Installing Debian......Page 25 Logging in Remotely......Page 27 Configuring the Network......Page 28 Changing the Default Debian Packages......Page 30 Setting Up Quotas......Page 31 Providing Domain Name Services......Page 33 Adding a Relational Database: MySQL......Page 35 Configuring Mail Securely with Postfix, POP3, and IMAP......Page 37 Putting Apache to Work......Page 48 Adding FTP Services with ProFTPD......Page 49 Summarizing Your Web Statistics with Webalizer......Page 50 Installing Perl Modules Needed by SpamAssassin......Page 51 What’s Next......Page 52 DNS Basics......Page 53 Advantages of Localized DNS Administration......Page 54 Components of BIND......Page 55 Setting Up a DNS Server......Page 56 Using a chroot Environment for Security......Page 57 Configuring an Authoritative DNS Server......Page 59 The Distributed Method of Resolving Domain Names......Page 60 Finding a Domain......Page 61 Primary and Secondary DNS Servers......Page 62 Caching-Only Servers......Page 64 named.conf......Page 65 The Primary Zone File......Page 68 Enhancements and advanced features......Page 70 Putting it all together......Page 73 The Reverse Zone File......Page 74 Testing Lookups......Page 75 Configuring the Secondary Nameserver......Page 76 BIND Tools......Page 77 nslookup......Page 78 rndc......Page 79 Cannot Connect Using rndc......Page 81 named Starts but Does Not Resolve Names......Page 82 Hosts Aren’t Recognized......Page 83 What’s Next......Page 86 An Initial Internet-Ready Environment......Page 88 Requirements......Page 89 Getting Started......Page 91 ISPConfig Directory Structure......Page 97 Adding Clients and Web Sites......Page 98 Managing Users and Email......Page 106 Email Client Configuration......Page 110 The Role of a Daemon-Monitoring Daemon......Page 111 Installing and Configuring monit......Page 113 What’s Next......Page 116 Mail......Page 117 Postfix, Sendmail, and Other MTAs......Page 118 Debian Postfix-Related Packages......Page 120 Installing Postfix on Debian......Page 121 Basic Postfix Configuration......Page 123 Testing Mail......Page 125 SASL Authentication......Page 126 Configuring Postfix with SASL to authenticate users with accounts......Page 127 The saslauthd daemon......Page 129 TLS Encryption......Page 130 Configuring POP3 and IMAP Mail Delivery Agents......Page 134 Email Client Configuration......Page 135 What’s Next......Page 136 Static and Dynamic Files......Page 137 A Simple LAMP Setup......Page 138 Apache......Page 139 MySQL......Page 140 Apache Configuration Files......Page 142 Configuration File Directives......Page 143 User and Group directives......Page 144 User files......Page 145 Containers and Aliases......Page 147 Aliases......Page 148 Server-Side Includes......Page 149 File suffix......Page 151 Name-based virtual hosts......Page 153 mod_vhost_alias......Page 154 Log Splitting and Rotation......Page 155 Analyzing Logs with Webalizer......Page 156 SSL/TLS Encryption......Page 157 suEXEC Support......Page 158 Benchmarking......Page 159 Installing and Administering Drupal......Page 160 Installing Drupal with apt-get......Page 161 Installing Drupal from Source......Page 162 Configuring Drupal......Page 163 Web Page Doesn’t Appear in Browser......Page 164 SSL Doesn’t Work......Page 167 Further Reading......Page 168 Load Balancing and High Availability......Page 169 IPVS on the Load Balancer......Page 170 ldirectord......Page 171 Configuring the Realservers (Apache Nodes)......Page 172 Configuring the Load Balancer......Page 173 Testing the System......Page 174 Adding Other LB Services......Page 176 Further Reading......Page 177 Local Network Services......Page 178 Introduction to Samba......Page 179 Configuring the Network......Page 180 DHCP......Page 183 Installing DHCP......Page 184 Starting Your DHCP Service......Page 186 Assigning IPv6 Addresses with radvd......Page 187 Gateway Services......Page 188 Another Approach to Gateway Services......Page 191 Print Services......Page 196 Printing Software Considerations......Page 197 Cross-Platform Printing......Page 198 Controlling Print Queues from the Command Line......Page 200 User Management......Page 201 Removing a User......Page 204 Sealing the Home Directory......Page 205 Graphical User Managers......Page 206 Why Virtualization Is Popular......Page 209 High-Performance Computing......Page 211 Rapid Provisioning......Page 212 How Virtualization Helps......Page 213 Installing Xen on Fedora 5......Page 214 Fedora Core 5......Page 216 Other guests......Page 217 Installing VMware......Page 219 Installing a VMware Guest OS......Page 224 Virtualization: A Passing Fad?......Page 225 Scripting......Page 226 bash Beginnings......Page 227 Pathnames and Permissions......Page 228 The Default Path......Page 229 I/O Redirection......Page 230 Variables......Page 232 Expressions......Page 233 If.........Page 234 Troubleshooting a Simple Script......Page 236 Loops......Page 238 cron Jobs......Page 240 Scripting Language Shootout......Page 241 Data Format: The /etc/passwd File......Page 242 The bash script......Page 243 The Perl script......Page 245 The PHP script......Page 247 The Python script......Page 248 Choosing a Scripting Language......Page 249 Further Reading......Page 250 Backing Up Data......Page 251 rsync Basics......Page 252 Making a User Backup Script......Page 254 Listing Files on the Backup Server......Page 255 Automated Backups......Page 256 tar Archives......Page 257 Extracting from an Archive......Page 258 A Complete Example of Packing and Unpacking with tar......Page 259 Saving Files on Optical Media......Page 260 Accessing Your CD-R Drive......Page 262 Preparing Files to Record on a CD-R......Page 263 Recording the CD-R......Page 264 Verifying the Recording......Page 265 Backing Up and Archiving to Tape with Amanda......Page 266 Installing Amanda......Page 267 Configuring Amanda......Page 268 Backing Up MySQL Data......Page 269 Adding Users......Page 272 Random Password Generator......Page 273 Authoritative DNS Lookup......Page 275 Sending Files Between Shell Sessions......Page 276 Integrating ssh and screen......Page 283 Index......Page 288 Linux System Administration 1 Table of Contents 6 Preface 10 How This Book Is Organized 11 Conventions Used in This Book 12 Using Code Examples 13 Safari庐 Enabled 13 How to Contact Us 13 Acknowledgments 14 Requirements for a Linux System Administrator 16 About This Book 17 How Can We Help? 17 Where Do You Start? 18 Do You Need a Book? 18 Who Needs You? 19 Help Wanted 19 Analyzing Skill Sets 20 What System Managers Should Know About Linux 21 What鈥檚 Next 22 Setting Up a Linux Multifunction Server 23 Server Requirements 24 Installing Debian 25 Logging in Remotely 27 Configuring the Network 28 Changing the Default Debian Packages 30 Setting Up Quotas 31 Providing Domain Name Services 33 Adding a Relational Database: MySQL 35 Configuring Mail Securely with Postfix, POP3, and IMAP 37 Putting Apache to Work 48 Adding FTP Services with ProFTPD 49 Summarizing Your Web Statistics with Webalizer 50 Synchronizing the System Clock 51 Installing Perl Modules Needed by SpamAssassin 51 What鈥檚 Next 52 The Domain Name System 53 DNS Basics 53 Advantages of Localized DNS Administration 54 Getting into the BIND 55 Components of BIND 55 Setting Up a DNS Server 56 Using a chroot Environment for Security 57 Configuring an Authoritative DNS Server 59 Your Responsibility in DNS 60 The Distributed Method of Resolving Domain Names 60 Finding a Domain 61 Answering Queries 62 Primary and Secondary DNS Servers 62 Caching-Only Servers 64 Editing the Configuration Files 65 named.conf 65 The Primary Zone File 68 Enhancements and advanced features 70 Putting it all together 73 The Reverse Zone File 74 PTR records 75 Testing Lookups 75 Configuring the Secondary Nameserver 76 BIND Tools 77 nslookup 78 rndc 79 Troubleshooting BIND 81 Cannot Connect Using rndc 81 named Starts but Does Not Resolve Names 82 Hosts Aren鈥檛 Recognized 83 What鈥檚 Next 86 An Initial Internet-Ready Environment 88 Installing ISPConfig 89 Requirements 89 Getting Started 91 ISPConfig Directory Structure 97 Setting Up a Server and Users with ISPConfig 98 Adding Clients and Web Sites 98 Managing Users and Email 106 User, email, home, and public web directories 110 Email Client Configuration 110 Safeguarding a Linux Web Server 111 The Role of a Daemon-Monitoring Daemon 111 Installing and Configuring monit 113 What鈥檚 Next 116 Mail 117 Key Mail Service Terms 118 Postfix, Sendmail, and Other MTAs 118 The Postfix SMTP Mail Server on Debian 120 Debian Postfix-Related Packages 120 Installing Postfix on Debian 121 Basic Postfix Configuration 123 Testing Mail 125 Adding Authentication and Encryption 126 SASL Authentication 126 Configuring Postfix with SASL to authenticate users with accounts 127 The saslauthd daemon 129 Configuring Postfix with SASL to authenticate users without accounts 130 TLS Encryption 130 Configuring POP3 and IMAP Mail Delivery Agents 134 Email Client Configuration 135 What鈥檚 Next 136 Administering Apache 137 Static and Dynamic Files 137 A Simple LAMP Setup 138 Installation 139 Apache 139 PHP 140 MySQL 140 Apache Configuration Files 142 Configuration File Directives 143 User and Group directives 144 Listen directive 145 DocumentRoot directive 145 Authentication and Authorization 145 User files 145 Group files 147 Containers and Aliases 147 Absolute pathnames: Directory 148 Relative pathnames: Location 148 Pattern matching: Files and FilesMatch 148 Aliases 148 Limits 149 Server-Side Includes 149 CGI 151 Location 151 File suffix 151 PHP Module-Specific Directives 153 Virtual Hosts 153 IP-based virtual hosts 153 Name-based virtual hosts 153 mod_vhost_alias 154 Logfiles 155 Log Splitting and Rotation 155 Splitting Logs with vlogger 156 Analyzing Logs with Webalizer 156 SSL/TLS Encryption 157 suEXEC Support 158 Benchmarking 159 Installing and Administering Drupal 160 Installing Drupal with apt-get 161 Installing Drupal from Source 162 Configuring Drupal 163 Troubleshooting 164 Web Page Doesn鈥檛 Appear in Browser 164 Virtual Hosts Don鈥檛 Work 167 SSI Doesn鈥檛 Work 167 CGI Program Doesn鈥檛 Run 167 SSL Doesn鈥檛 Work 167 Further Reading 168 Load-Balanced Clusters 169 Load Balancing and High Availability 169 Load-Balancing Software 170 IPVS on the Load Balancer 170 ldirectord 171 Configuring the Realservers (Apache Nodes) 172 Configuring the Load Balancer 173 Testing the System 174 Adding HA to LB 176 Adding Other LB Services 176 Scaling Without LB and HA 177 Further Reading 177 Local Network Services 178 Distributed Filesystems 179 Introduction to Samba 179 Configuring the Network 180 DHCP 183 Installing DHCP 184 Starting Your DHCP Service 186 Providing Static IP Addresses 187 Assigning IPv6 Addresses with radvd 187 Gateway Services 188 Another Approach to Gateway Services 191 Print Services 196 Printing Software Considerations 197 Cross-Platform Printing 198 Controlling Print Queues from the Command Line 200 User Management 201 Removing a User 204 Sealing the Home Directory 205 Graphical User Managers 206 Virtualization in the Modern Enterprise 209 Why Virtualization Is Popular 209 High-Performance Computing 211 Business Continuity and Workload Management 212 Rapid Provisioning 212 How Virtualization Helps 213 Installing Xen on Fedora 5 214 Installing a Xen Guest OS 216 Fedora Core 5 216 Other guests 217 Installing VMware 219 Installing a VMware Guest OS 224 Virtualization: A Passing Fad? 225 Scripting 226 bash Beginnings 227 Pathnames and Permissions 228 The Default Path 229 I/O Redirection 230 Variables 232 Useful Elements for bash Scripts 233 Expressions 233 Arithmetic 234 If... 234 Troubleshooting a Simple Script 236 Loops 238 cron Jobs 240 Scripting Language Shootout 241 Data Format: The /etc/passwd File 242 Script Versions 243 The bash script 243 The Perl script 245 The PHP script 247 The Python script 248 Choosing a Scripting Language 249 Further Reading 250 Backing Up Data 251 Backing Up User Data to a Server with rsync 252 rsync Basics 252 Making a User Backup Script 254 Listing Files on the Backup Server 255 Restoring Lost or Damaged Files 256 Automated Backups 256 tar Archives 257 Creating a New Archive 258 Extracting from an Archive 258 A Complete Example of Packing and Unpacking with tar 259 Summary 260 Saving Files on Optical Media 260 Accessing Your CD-R Drive 262 Setting Defaults 263 Preparing Files to Record on a CD-R 263 Recording the CD-R 264 Verifying the Recording 265 Backing Up and Archiving to Tape with Amanda 266 Installing Amanda 267 Configuring Amanda 268 Restoring Files Backed Up by Amanda 269 Backing Up MySQL Data 269 bash Script Samples 272 Adding Users 272 Random Password Generator 273 Authoritative DNS Lookup 275 Sending Files Between Shell Sessions 276 Integrating ssh and screen 283 Index 288 If you're an experienced system administrator looking to acquire Linux skills, or a seasoned Linux user facing a new challenge, __Linux System Administration__ offers practical knowledge for managing a complete range of Linux systems and servers. The book summarizes the steps you need to build everything from standalone SOHO hubs, web servers, and LAN servers to load-balanced clusters and servers consolidated through virtualization. Along the way, you'll learn about all of the tools you need to set up and maintain these working environments. Linux is now a standard corporate platform with users numbering in the hundreds of millions, and there is a definite shortage of talented administrators. __Linux System Administration__ is ideal as an introduction to Linux for Unix veterans, MCSEs, and mainframe administrators, and as an advanced (and refresher) guide for existing Linux administrators who will want to jump into the middle of the book. Inside, you'll learn how to: * Set up a stand-alone Linux server * Install, configure, maintain, and troubleshoot a DNS server using BIND * Build an Internet server to manage sites, perform email and file transfers, and more * Set up an email service for a small-to-medium-sized site, complete with authentication * Install and configure Apache, PHP, and MySQL on a web server built from scratch * Combine computers into a load-balanced Apache web server cluster based on the free Linux Virtual Server * Set up local network services from distributed file systems to DHCP services, gateway services, print services, user management and more * Use Linux virtualization with Xen or VMWare to run multiple kernels on one piece of hardware; manage each kernel's access to processor time, devices, and memory * Create shell scripts and adapt them for your own needs * Back up and restore data with __rsync, tar, cdrecord__, Amanda, and MySQL tools __Linux System Administration__ is not only knowledgeable and practical, but convenient. The ingredients for this book had been scattered throughout mailing lists, forums, and discussion groups, as well as books, periodicals, and the experiences of colleagues. Everything is now in one handy guide. In the course of their research, the authors also solved many problems whose solutions were completely undocumented. They now pass their lessons on to you.