CompTIA Linux+ XK0-005 Exam Cram

At the impressionable age of 14, William “Bo” Rothwell crossed paths with a TRS-80 Micro Computer System (affectionately known as a “Trash 80”). Soon after the adults responsible for Bo made the mistake of leaving him alone with the TSR-80, he dismantled it and held his first computer class, showing his friends what made this “computer thing” work.   Since that experience, Bo's passion for understanding how computers work and sharing this knowledge with others has resulted in a rewarding career in IT training. His experience includes Linux, Unix, IT security, DevOps, cloud technologies, and programming languages such as Perl, Python, Tcl, and BASH. He is the founder and lead instructor of One Course Source, an IT training organization.

    Introduction. . . . . . . . . . . . xxiv

 

Part I: System Management

CHAPTER 1: Linux Fundamentals. . . . . . . . . . . 1

    Filesystem Hierarchy Standard (FHS).. . . . . . . 1

    Basic Boot Process.. . . . . . . . . . 3

    Kernel Panic. . . . . . . . . . . 10

    Device Types in /dev.. . . . . . . . . 10

    Basic Package Compilation from Source.. . . . . . 13

    ./configure.. . . . . . . . . . 13

    make.. . . . . . . . . . . 15

    make install.. . . . . . . . . . 16

    Storage Concepts.. . . . . . . . . . 16

    Listing Hardware Information.. . . . . . . . 22

 

CHAPTER 2: Manage Files and Directories.. . . . . . . . . 27

    File Editing.. . . . . . . . . . . 27

    File Compression, Archiving, and Backup. . . . . . 36

    File Metadata.. . . . . . . . . . . 41

    Soft and Hard Links.. . . . . . . . . 43

    Copying Files Between Systems.. . . . . . . 46

    File and Directory Operations.. . . . . . . . 49

 

CHAPTER 3: Configure and Manage Storage Using the Appropriate Tools.. . . 57

    Disk Partitioning.. . . . . . . . . . 57

    Mounting Local and Remote Devices.. . . . . . 61

    Filesystem Management. . . . . . . . . 66

    Monitoring Storage Space and Disk Usage. . . . . . 70

    Creating and Modifying Volumes Using Logical Volume Manager (LVM).. . . . . . . . . . 71

    Inspecting RAID Implementations.. . . . . . . 75

    Storage Area Network (SAN)/Network-Attached Storage (NAS). . 78

    Storage Hardware.. . . . . . . . . . 82

 

CHAPTER 4: Configure and Use the Appropriate Processes and Services.. . . 85

    System Services. . . . . . . . . . 85

    Scheduling Services. . . . . . . . . . 90

    Process Management. . . . . . . . . 97

 

CHAPTER 5: Use the Appropriate Networking Tools or Configuration Files. . . 113

    Interface Management.. . . . . . . . . 113

    Name Resolution.. . . . . . . . . . 122

    Network Monitoring.. . . . . . . . . 127

    Remote Networking Tools.. . . . . . . . 132

 

CHAPTER 6: Build and Install Software. . . . . . . . . 139

    Package Management.. . . . . . . . . 139

    Sandboxed Applications.. . . . . . . . . 149

    System Updates.. . . . . . . . . . 150

 

Part II: Security

CHAPTER 7: Manage Software Configurations.. . . . . . . . 155

    Updating Configuration Files.. . . . . . . . 155

    Configure Kernel Options.. . . . . . . . 158

    Configure Common System Services.. . . . . . . 165

    Localization.. . . . . . . . . . . 172

 

CHAPTER 8: Security Best Practices in a Linux Environment.. . . . . 177

    Managing Public Key Infrastructure (PKI) Certificates.. . . 177

    Certificate Use Cases. . . . . . . . . 181

    Authentication.. . . . . . . . . . 181

    Linux Hardening.. . . . . . . . . . 188

 

CHAPTER 9: Implement Identity Management. . . . . . . . 201

    Account Creation and Deletion. . . . . . . . 201

    .bashrc. . . . . . . . . . . 212

    Account Management.. . . . . . . . . 212

 

CHAPTER 10: Implement and Configure Firewalls.. . . . . . . . 219

    Firewall Use Cases.. . . . . . . . . . 219

    Common Firewall Technologies.. . . . . . . 221

    Key Firewall Features.. . . . . . . . . 223

 

CHAPTER 11: Configure and Execute Remote Connectivity for System Management.. 227

    SSH.. . . . . . . . . . . . 227

    Executing Commands as Another User.. . . . . . 235

 

CHAPTER 12: Apply the Appropriate Access Controls. . . . . . . 241

    File Permissions.. . . . . . . . . . 241

    Security-Enhanced Linux (SELinux).. . . . . . . 243

    AppArmor.. . . . . . . . . . . 247

    Command-Line Utilities.. . . . . . . . . 250

 

Part III: Scripting, Containers, and Automation

CHAPTER 13: Create Simple Shell Scripts to Automate Common Tasks. . . . 265

    Shell Script Elements.. . . . . . . . . 265

    Common Script Utilities.. . . . . . . . . 286

    Environment Variables. . . . . . . . . 298

    Relative and Absolute Paths.. . . . . . . . 302

 

CHAPTER 14: Perform Basic Container Operations. . . . . . . 305

    Container Management.. . . . . . . . . 305

    Container Image Operations.. . . . . . . . 312

 

CHAPTER 15: Perform Basic Version Control Using Git.. . . . . . . 317

    Introduction to Version Control and Git.. . . . . . 317

    clone.. . . . . . . . . . . . 321

    push.. . . . . . . . . . . . 323

    pull.. . . . . . . . . . . . 324

    commit.. . . . . . . . . . . . 324

    add.. . . . . . . . . . . . 325

    branch/checkout.. . . . . . . . . . 325

    tag.. . . . . . . . . . . . 329

    gitignore.. . . . . . . . . . . 330

 

CHAPTER 16: Common Infrastructure as Code Technologies.. . . . . 333

    File Formats. . . . . . . . . . . 334

    Utilities.. . . . . . . . . . . . 335

    Continuous Integration/Continuous Deployment (CI/CD).. . . 338

    Advanced Git Topics.. . . . . . . . . 339

 

CHAPTER 17: Container, Cloud, and Orchestration Concepts.. . . . . 343

    Kubernetes Benefits and Application Use Cases.. . . . . 344

    Single-Node, Multicontainer Use Cases. . . . . . 346

    Container Persistent Storage.. . . . . . . . 346

    Container Networks.. . . . . . . . . 347

    Service Mesh.. . . . . . . . . . . 349

    Bootstrapping. . . . . . . . . . . 350

    Container Registries.. . . . . . . . . 350

 

Part IV: Troubleshooting

CHAPTER 18: Analyze and Troubleshoot Storage Issues.. . . . . . 353

    High Latency.. . . . . . . . . . . 353

    Input/Output Operations per Second (IOPS) Scenarios.. . . 354

    Capacity Issues.. . . . . . . . . . 355

    Filesystem Issues. . . . . . . . . . 358

    I/O Scheduler. . . . . . . . . . . 359

    Device Issues.. . . . . . . . . . . 360

    Mount Option Problems.. . . . . . . . . 363

 

CHAPTER 19: Analyze and Troubleshoot Network Resource Issues.. . . . 365

    Network Configuration Issues.. . . . . . . . 365

    Firewall Issues.. . . . . . . . . . 367

    Interface Errors.. . . . . . . . . . 367

    Bandwidth Limitations. . . . . . . . . 373

    Name Resolution Issues. . . . . . . . . 374

    Testing Remote Systems.. . . . . . . . . 375

 

CHAPTER 20: Analyze and Troubleshoot Central Processing Unit (CPU) and Memory Issues. . . . 379

    Runaway Processes.. . . . . . . . . . 379

    Zombie Processes.. . . . . . . . . . 380

    High Load Average.. . . . . . . . . . 383

    High Run Queues.. . . . . . . . . . 384

    CPU Times.. . . . . . . . . . . 384

    CPU Process Priorities.. . . . . . . . . 384

    Memory Exhaustion.. . . . . . . . . 385

    Out of Memory (OOM). . . . . . . . . 385

    Swapping.. . . . . . . . . . . 386

    Hardware. . . . . . . . . . . 388

 

CHAPTER 21: Analyze and Troubleshoot User Access and File Permissions. . . 397

    User Login Issues.. . . . . . . . . . 397

    User File Access Issues. . . . . . . . . 400

    Password Issues. . . . . . . . . . 404

    Privilege Elevation.. . . . . . . . . . 405

    Quota Issues. . . . . . . . . . . 405

 

CHAPTER 22: Use systemd to Diagnose and Resolve Common Problems with a Linux System. . . . . 411

    Unit Files. . . . . . . . . . . 412

    Common Problems.. . . . . . . . . . 429

 

9780137898558, TOC, 8/11/2022