Master essential Linux troubleshooting skills with this comprehensive guide. Learn proven techniques for diagnosing and fixing common Linux problems, from boot issues to package management errors. This masterclass covers critical server troubleshooting scenarios including network configuration, LVM management, SELinux challenges, and Apache service errors. Perfect for Linux admins seeking practical command line troubleshooting tools and solutions for performance issues. Follow along with real RHEL examples as we demonstrate step-by-step recovery techniques for system crashes, configuration problems, and service failures. Whether you're preparing for Linux admin interview questions or need a refresher on troubleshooting commands, this guide provides the essential knowledge to solve Linux server issues efficiently.
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How to rebuild the initial ramdisk image in Red Hat Enterprise Linux
https://access.redhat.com/solutions/1958
RHEL Troubleshooting Challenge 5
https://red.ht/ts-5i
Nate Lager: https://twitter.com/gangrif
Commands used:
systemctl, journalctl, ss, nmap, cat, od, dos2unix, fsck, mount, grub2-install, df, chroot, dnf, dnf (yum), rpm, subscription-manager, man, ping, tracepath, traceroute, dig, ip, route, nmcli
00:00 Logical Volume Manager
00:15 Understanding LVM Abstraction Layers
00:43 Volume Groups and Logical Volumes
01:21 Key Commands for LVM
04:11 Manipulating Physical Volumes
04:35 Expanding Volume Groups
05:30 Whiteboarding LVM Concepts
09:19 Adding Disk Space to Logical Volumes
14:59 Practical Example: Extending File Systems
23:05 Troubleshooting and Advanced LVM Operations
32:23 Creating and Managing Logical Volumes
40:29 Network Troubleshooting Tools
40:34 Understanding Ping and Its Output
41:54 Exploring TracePath and TraceRoute
45:25 DNS Lookup with Dig
47:02 Local System Network Settings with IP and Route
49:10 Network Manager Command Line Interface (NMCLI)
52:48 Whiteboard Explanation of Network Flow
56:27 DNS and Network Flow
01:03:07 DNS Troubleshooting
01:14:09 Troubleshooting DNS Server Issues
01:14:32 Understanding Gateway and Routing Problems
01:17:12 Identifying and Fixing Default Gateway Issues
01:20:29 Network Interface Configuration and Multiple Gateways
01:23:09 ICMP, UDP, and TCP Protocols in Network Diagnostics
01:27:38 File System and Bootloader Tools
01:31:13 Rescue Mode and Boot Process
01:35:23 Boot Process Breakdown and Troubleshooting
01:44:33 Practical Boot Troubleshooting Scenarios
02:13:50 Setting Up the Rescue System
02:14:50 Mounting and Binding Directories
02:16:28 Creating and Editing Repo Files
02:18:05 Reinstalling Packages with DNF
02:21:38 Reboot
02:24:37 Troubleshooting Package Transactions
02:24:48 Using DNF for Package Management
02:28:41 Exploring RPM and Subscription Manager
02:34:01 Understanding Package Transactions
02:44:49 Diagnosing and Fixing Package Issues
02:50:44 Rolling Back Transactions
03:01:40 Identifying and Handling Third-Party Packages
03:07:57 Common Issues with Source Code Installation
03:09:25 Package Management Best Practices
03:12:17 Exploring Extra Repositories
03:13:07 Building and Signing Your Own RPMs
03:13:55 A Young Admin's Journey
03:16:50 Essential Troubleshooting Tools
03:17:14 Systemctl and Journalctl Commands
03:17:56 Editing Service Files with Systemctl
03:20:33 Using Journalctl for Logs
03:21:17 Network Troubleshooting with SS and Nmap
03:26:13 Diagnosing Apache Service Issues
03:34:44 SELinux and Port Binding Issues
03:41:28 Containerization and Port Management
03:49:31 Enabling Services at Boot
03:54:09 Handling Unprintable Characters in Config Files
04:04:33 Q&A