Linux Server Admin with Fexingo: Sysadmin, Bash, and Server Engineering

Episode 79 of Linux Server Admin with Fexingo digs into network bonding — combining multiple physical NICs into a single logical interface for failover and increased throughput. Lucas and Luna walk through the main bonding modes: active-backup for simple redundancy, balance-xor and 802.3ad for load balancing, and balance-alb for adaptive load balancing without switch support. They explain how to c...

Episode 78 of Linux Server Admin with Fexingo dives into VLAN tagging on Linux servers using systemd-networkd. Lucas and Luna walk through a real-world scenario: a multi-tenant web host needing to isolate customer traffic without buying new hardware. They explain how to configure 802.1Q VLANs on a single physical interface, assign IPs, and verify connectivity — all with systemd-networkd's clean .n...

In this episode of Linux Server Admin, Lucas and Luna dive into running containers without root privileges using Podman and Linux namespaces. You'll learn how Podman differs from Docker in its daemonless architecture, how user namespaces map container root to an unprivileged host user, and why this matters for security in multi-tenant environments. Lucas walks through a practical example of deploy...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into full-disk encryption for Linux servers using LUKS (Linux Unified Key Setup). They explain why disk encryption matters for data-at-rest protection, walk through a practical example of encrypting a secondary drive on Ubuntu Server 22.04 LTS, and discuss key management options including passphrases, keyfiles, and TPM-based u...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna walk through nftables, the modern replacement for iptables on Linux servers. They cover the key differences, a concrete migration example, and practical tips for managing firewall rules with nftables. Lucas explains the nftables syntax, sets, and maps, and shows how to migrate common iptables rules to nftables. Luna asks about perf...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into SSH key-based authentication and server hardening. They walk through generating Ed25519 key pairs, disabling password authentication, configuring sshd for key-only access, and implementing fail2ban to block brute-force attacks. The discussion covers practical steps like using ssh-copy-id, setting proper permissions on ~/....

In episode 73 of Linux Server Admin with Fexingo, Lucas and Luna dive deep into AIDE (Advanced Intrusion Detection Environment) for Linux server file integrity monitoring. They explain how AIDE creates a baseline database of file checksums, permissions, and metadata, then compares current state to detect unauthorized changes. Using a real-world example of a compromised web server, Lucas walks thro...

In this episode, Lucas and Luna walk through a real-world scenario where a Linux server fails to boot after a botched kernel update. Lucas explains how to break into rescue mode via the GRUB boot loader, mount the root filesystem read-write, chroot into the broken environment, and roll back the offending kernel package. He also covers how to rebuild the initramfs when drivers are missing, using dr...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the world of Linux control groups version 2 (cgroups v2). They explain why cgroups v2 is now the default on most modern distributions, how it differs from the older v1 interface, and walk through a practical example of limiting CPU and memory usage for a resource-hungry database process. The hosts discuss the unified hier...

In episode 70 of Linux Server Admin with Fexingo, Lucas and Luna dive into Linux server audit logs for incident response. They walk through a real-world scenario: detecting an unauthorized SSH key addition on a production server using auditd rules, ausearch, and aureport. Lucas explains how to set up watches on critical files, interpret audit events, and generate a concise timeline of attacker act...

In this episode, Lucas and Luna dive into automating Linux server configuration using Ansible. They walk through a real-world scenario: setting up a web server stack (Nginx, Node.js, PostgreSQL) on a fresh Ubuntu 24.04 host using a single Ansible playbook. Lucas explains the key concepts—inventory files, idempotency, YAML syntax—and contrasts Ansible with shell scripts and Puppet. Luna asks about...

In this episode of Linux Server Admin, Lucas and Luna dive into the process of building a custom initramfs for Linux servers. They explain why you might want to replace the distribution's default initramfs—such as for faster boot times, smaller size, or specialized hardware—and walk through the key steps: compiling a kernel module, creating a minimal root filesystem with BusyBox, and using mkinitr...

In this episode of Linux Server Admin, Lucas and Luna dive into the practical side of keeping server clocks accurate using Chrony, the modern NTP implementation. They discuss why time sync matters more than most sysadmins think—from log correlation to certificate validation to file timestamps. Lucas walks through installing Chrony, configuring it with multiple NTP pools and a local hardware clock,...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into Linux auditd, the powerful audit framework built into the kernel. They explain how auditd can log security-relevant events like file accesses, system calls, and user logins, and how to configure custom rules to detect suspicious behavior. Using real examples, they walk through setting up audit rules for monitoring changes...

Episode 65 of Linux Server Admin with Fexingo dives into automated security patching on Linux servers using unattended-upgrades. Lucas and Luna walk through configuring the tool for Debian and Ubuntu systems, setting up automatic reboot windows with systemd timers, and monitoring update logs to avoid surprises. They discuss real-world trade-offs: patching speed vs. stability risk, and why you shou...

Episode 64 of Linux Server Admin with Fexingo. Lucas and Luna dive into systemd-journald for centralized log management on Linux servers. Lucas explains why traditional syslog falls short for modern workloads—too chatty, hard to parse, no structured metadata. He walks through configuring journald to persist logs to disk for crash forensics, limiting journal size to 500 MB with MaxRetentionSec, and...

In episode 63 of Linux Server Admin with Fexingo, Lucas and Luna dive into proactive hardware monitoring for Linux servers using smartctl for disk health and IPMI for chassis sensors. They walk through a real scenario where a missing drive was caught by a scheduled smartctl scan before data loss, and how to set up ipmitool to monitor temperature and fan speed on Dell PowerEdge servers. Lucas expla...

Episode 62 of Linux Server Admin with Fexingo dives into the practical pain of slow package updates when managing fleets of Ubuntu or Debian servers. Lucas and Luna walk through setting up apt-cacher-ng, a caching proxy that slashes redundant downloads and LAN bandwidth. They cover installation steps, client configuration, cache tuning for a 50-node environment, and how to avoid stale cache gotcha...

In this episode, Lucas and Luna dive into Linux server disk I/O performance tuning by focusing on the three main I/O schedulers available in the modern Linux kernel: CFQ, Deadline, and noop. They explain how each scheduler works under the hood, when to choose one over the other, and walk through practical commands to check and change the scheduler on a running system. Using examples like a busy da...

Have you ever rebooted a Linux server only to have it drop you into a busybox shell instead of booting normally? In this episode of Linux Server Admin, Lucas and Luna walk through the exact steps to diagnose and recover from initramfs failures. They cover how to identify the root cause by examining kernel panic messages, using the emergency shell to check filesystem integrity with fsck, and extrac...

When your server talks to clients halfway around the world, default TCP settings can choke performance. In this episode, Lucas and Luna explain how to tune Linux server TCP parameters for high-latency links. They walk through a real-world case: a video transcoding service in Singapore serving users in South America, where default TCP windowing caused throughput to stall at 12 Mbps. Learn how adjus...

In this episode, Lucas and Luna dive deep into Linux network namespaces as a practical tool for multi-tenant server isolation. They walk through a real-world scenario: setting up two isolated network stacks on a single host using 'ip netns', configuring virtual Ethernet pairs, and assigning IP addresses so each namespace can talk to the outside world independently. Lucas explains the difference be...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the practical side of container runtimes—specifically, how to choose between Docker, containerd, and Podman for production server workloads. They break down the architecture of each runtime, explain how the Open Container Initiative (OCI) standards ensure interoperability, and walk through a real-world scenario: deploying...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into a powerful but often overlooked feature of Logical Volume Manager (LVM): snapshot-based backups for fast recovery. They walk through a real-world scenario where a failed software update on a production database server requires rolling back in under 10 minutes. Lucas explains how LVM snapshots work at the block level, the...

Episode 55 of Linux Server Admin tackles a common but infuriating problem: DNS resolution failures that can cripple server connectivity. Lucas and Luna walk through a real-world scenario where an application suddenly can't reach external APIs. They cover the diagnostic toolkit — digging into /etc/resolv.conf, testing with dig and nslookup, checking systemd-resolved stubs, and tracing timeouts with...