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

Lucas and Luna dive into Linux namespace isolation using the 'unshare' command. They explain how unshare allows you to create isolated environments for processes without needing full container runtimes. Using a concrete example, they walk through creating a namespace with its own mount table, process tree, and network stack, showing how it differs from tools like Docker and LXC. They discuss use c...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into etckeeper, a lightweight tool that automatically version-controls your /etc directory with Git. They walk through installation, configuration, and a real-world scenario where etckeeper saved a sysadmin after a botched Nginx config edit. You'll learn how to set it up in under five minutes, how it integrates with package ma...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into network performance tuning on Linux servers using the sysctl utility. They focus on a practical case: optimizing TCP stack parameters for a high-traffic web server handling thousands of concurrent connections. Lucas explains how to adjust settings like net.core.somaxconn, net.ipv4.tcp_tw_reuse, and net.ipv4.tcp_fin_timeou...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into network bonding for Linux servers using the modern teamd daemon. They explain how to combine multiple physical NICs into a single logical interface for redundancy and increased throughput, covering active-backup and load-balancing modes. The hosts walk through a practical example of configuring a two-NIC bond on a CentOS...

Episode 100 of Linux Server Admin with Fexingo: Lucas and Luna dive into performance tuning with Tuned, the Linux systemd service that applies predefined profiles to optimize server workloads. They break down the difference between virtual-guest, throughput-performance, and latency-performance profiles using a real-world example of a PostgreSQL database server struggling with background batch jobs...

In episode 99 of Linux Server Admin with Fexingo, Lucas and Luna dive into Linux control groups (cgroups) version 2, a powerful kernel feature for limiting, accounting, and isolating CPU, memory, and I/O usage of processes. They walk through a concrete example: setting up a memory limit on a web server process to prevent an out-of-control PHP-FPM pool from crashing the whole machine. Along the way...

In episode 98 of Linux Server Admin with Fexingo, Lucas and Luna dive into the world of FUSE — Filesystem in Userspace. They explain how FUSE lets you build custom file systems without kernel modules, walk through a real example of mounting an S3 bucket as a local directory using s3fs-fuse, discuss performance trade-offs (context-switch overhead vs. development speed), and share practical tips for...

In this episode, Lucas and Luna dive into full-disk encryption for Linux servers using LUKS (Linux Unified Key Setup) and Clevis for automatic unlocking. Lucas explains how LUKS works at the block layer, the importance of LUKS header backups, and how Clevis integrates with network-bound disk encryption (NBDE) using Tang servers. They walk through a practical example: setting up LUKS on a new disk,...

Episode 96 of Linux Server Admin with Fexingo dives into SSH certificate authentication as a modern alternative to traditional key-based access. Lucas and Luna walk through the practical setup using a custom certificate authority, from generating the CA key pair to signing host and user certificates, configuring sshd, and deploying the trusted CA public key across a small server fleet. They explai...

Episode 95 gets into the weeds of Linux server time synchronization using Chrony instead of the older NTP daemon. Lucas and Luna walk through why accurate time matters more than most sysadmins think — from certificate validation to log correlation to distributed database consistency. They cover the key differences between Chrony and ntpd, how to configure multiple time sources, how to check synchr...

Episode 94 of Linux Server Admin with Fexingo dives into systemd timer units as a modern replacement for cron. Lucas and Luna walk through creating a daily backup timer on an Ubuntu 24.04 server, complete with a real example: a timer that triggers a script to archive Nginx logs every morning at 3 AM. They cover timer syntax, calendar events like 'daily' and 'weekly', monotonic timers like 'OnBootS...

Kernel Same-page Merging (KSM) is a Linux kernel feature that deduplicates identical memory pages across processes, dramatically reducing RAM usage in virtualized and containerized environments. In this episode, Lucas and Luna dive into how KSM works under the hood, when to enable it, and real-world performance trade-offs. They walk through enabling KSM on a Debian 12 server, tuning merge_across_n...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into Linux server auditing using auditd. They explain how to set up audit rules to monitor file access, track user commands, and detect unauthorized changes. Key topics include installing auditd, creating persistent rules with auditctl, generating reports with aureport, and searching logs with ausearch. The hosts use a concret...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into iptables — the classic packet filtering framework still essential for sysadmins managing Linux servers. They walk through real-world examples: setting up rules to allow SSH while blocking brute-force attempts, creating stateful firewall policies, and logging dropped packets for troubleshooting. Lucas explains the differen...

In Episode 90 of Linux Server Admin with Fexingo, Lucas and Luna dive into IPv6 configuration for Linux servers using systemd-networkd. They explain why IPv6 matters in 2026, how to set up SLAAC and static addressing, and common pitfalls like duplicate address detection failures. Lucas walks through a real-world example from his home lab, covering sysctl tunables, router advertisement handling, an...

In episode 89 of Linux Server Admin with Fexingo, Lucas and Luna dive into load balancing Linux servers using HAProxy. They walk through a concrete setup: a pair of web servers behind a single HAProxy frontend, with health checks and round-robin distribution. The conversation covers why you might choose HAProxy over nginx for layer 4 balancing, how to configure backend pools with check intervals,...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into strace — the powerful Linux system call tracer. They explain what strace does, walk through a real-world example of diagnosing a slow web server using strace -c, and cover practical flags like -f for tracing child processes and -e for filtering specific syscalls. They also discuss common pitfalls, such as performance impa...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into TCP Wrappers — a classic host-based access control system for Linux servers. They explain how TCP Wrappers work with the libwrap library, how to configure /etc/hosts.allow and /etc/hosts.deny to permit or deny connections by IP address or hostname, and the security implications for services like SSH and vsftpd. Lucas shar...

Episode 86 of Linux Server Admin with Fexingo dives into disk quotas on Linux servers. Lucas and Luna walk through setting up user and group quotas with the classic quota tools, configuring quota on an ext4 filesystem, using repquota and warnquota for monitoring and enforcement, and best practices for multi-user environments. They discuss real-world tradeoffs like performance overhead, NFS compati...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into systemd-journald as a centralized logging solution. They explain how to configure journald to forward logs to a remote server using systemd-journal-upload, enabling secure, encrypted log aggregation across your fleet without third-party tools. The hosts walk through setting up the receiving server with systemd-journal-rem...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into logrotate, the indispensable tool for managing server log files. They explain why log rotation prevents disk-full disasters, break down the configuration syntax with a real-world example from an Nginx server handling 50,000 requests per day, and show how to set compression, retention policies, and post-rotation scripts. L...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into Tailscale as a modern solution for secure remote access to Linux servers without traditional VPN complexity. They walk through setup on Ubuntu 24.04, discuss subnet routing for reaching devices behind a server, and compare Tailscale's approach to WireGuard and OpenVPN. The conversation covers authentication via SSO provid...

Learn how to use Falco, the open-source runtime security tool, to detect threats on Linux servers in real time. Lucas and Luna walk through installing Falco, writing custom rules, and interpreting alerts to catch suspicious behavior like reverse shells or privilege escalation. They use a concrete example of a compromised web server to show how Falco's output can be integrated with systemd journal...

In episode 81 of Linux Server Admin with Fexingo, Lucas and Luna explore Logwatch, the lightweight log analysis tool that sends daily server reports via email. They walk through installation, basic configuration, service-specific filtering for SSH, Apache, and fail2ban, and tuning report verbosity. Lucas shares a real-world example where Logwatch caught a brute-force attack on a staging server bef...

In this episode, Lucas and Luna dive into HashiCorp Vault for Linux server secret management. They cover initializing and unsealing Vault, setting up a secret backend for database credentials, and integrating with applications via the Vault Agent. Using a concrete example of rotating PostgreSQL credentials, they explain why Vault is essential for modern server security — especially in multi-server...