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

Lucas walks Luna through the blue-green deployment pattern, a strategy that eliminates application downtime during updates by running two identical production environments and switching traffic atomically. They break down the exact steps: provisioning a standby environment, running health checks on the new version, flipping the load balancer, and rolling back instantly if something breaks. Lucas u...

Episode 21 of Linux Server Admin with Fexingo dives into the overlooked art of outbound email from headless servers. Lucas and Luna unpack why cron output, system alerts, and automated reports often vanish into the void, and how a tiny tool called nullmailer fixes it without a full mail stack. They walk through a real-world case: a staging server silently dropping backup failure alerts for six mon...

In this episode, Lucas and Luna dive into why a dedicated WireGuard VPN mesh beats traditional VPN setups for server-to-server communication. They walk through a real-world example of a three-node cluster where tailscale-style WireGuard overlay simplified firewall rules, reduced latency by 12 milliseconds, and cut configuration time from hours to minutes. Lucas explains the kernel-level efficiency...

Before you run apt upgrade or yum update, there's a better safety net than hoping you can roll back. In this episode, Lucas and Luna dive into why filesystem snapshots — using LVM or ZFS — should be a standard pre-update ritual. They walk through a real scenario: a production server that survived a broken kernel update only because the sysadmin had a five-second snapshot routine. They explain the...

Episode 18 of Linux Server Admin with Fexingo tackles the Linux kernel's Out-Of-Memory (OOM) Killer—a necessary but brutal mechanism that can kill critical services when memory pressure spikes. Hosts Lucas and Luna explore why the OOM Killer often targets the wrong process, how systemd's OOMD (introduced in v243) gives sysadmins fine-grained control over which services get sacrificed, and a real-w...

Episode 17 of Linux Server Admin with Fexingo dives into the case for a dedicated log aggregation pipeline. Lucas and Luna walk through a real-world scenario where a production outage was prolonged by 45 minutes because logs were scattered across 12 servers with no central aggregation. They explain why tools like the ELK stack or Loki reduce mean time to resolution, how a centralized pipeline turn...

In this episode of Linux Server Admin, Lucas and Luna explore why a dedicated time-series database (TSDB) like InfluxDB or VictoriaMetrics can transform how you handle server metrics, logs, and monitoring data. They walk through a real-world scenario: a mid-size e-commerce company whose Prometheus setup buckled under 500,000 metrics per second, leading to dropped data and skewed alerts. Lucas expl...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna argue that every production Linux server should run its own dedicated monitoring stack, separate from the application infrastructure. They walk through a real-world case where a shared Prometheus instance caused a cascading failure in a SaaS company's monitoring, and explain how a dedicated stack with Grafana, Prometheus, and Alert...

Episode 14 of Linux Server Admin with Fexingo: Sysadmin, Bash, and Server Engineering. Lucas and Luna explain why routing all SSH traffic through a dedicated bastion host dramatically reduces your attack surface and simplifies compliance. They walk through a real-world setup using a $5/month VPS as a jump box, discuss sshd hardening (disabling root login, key-only auth, port knocking), and cover a...

Lucas and Luna explain the concept of immutable root filesystems for Linux servers—why making the root partition read-only can stop configuration drift, prevent malware persistence, and simplify updates. They dive into how Fedora Silverblue and openSUSE MicroOS implement this, the trade-offs for package management, and why it's gaining traction for production workloads in 2026. No theoretical fluf...

Episode 12 of Linux Server Admin with Fexingo digs into a common but overlooked failure point in server management: running Ansible from a personal workstation. Lucas and Luna walk through a real-world case where a sysadmin's laptop battery died mid-playbook, leaving a fleet of 200 production servers in an inconsistent state. They explain why a dedicated, stateless Ansible control machine — a chea...

Episode 11 of Linux Server Admin tackles a silent server killer: clock drift. Lucas and Luna explain why even a 50-millisecond offset can break database replication, certificate validation, and distributed consensus. They walk through a real example of a PostgreSQL cluster that failed silently because chrony wasn't configured to poll multiple upstream servers. They compare ntpd vs chronyd vs syste...

When your production server suddenly drops into a kernel panic, the instinct is to reboot and hope it doesn't happen again. Lucas and Luna walk through a real case from a fintech startup where a misconfigured memory module caused intermittent panics across a 200-node cluster. They explain how to capture crash dumps, read the stack trace to identify the offending driver or hardware, and use tools l...

In this episode of Linux Server Admin with Fexingo, hosts Lucas and Luna explore the real-world impact of container orchestration on Linux server engineering. They trace the journey from early Docker days to Kubernetes becoming the default deployment platform for everything from microservices to batch jobs. Lucas breaks down why container orchestration isn't just for tech giants: small teams can s...

Episode 8 of Linux Server Admin with Fexingo. Lucas and Luna drill into disk I/O latency — the silent performance killer that most sysadmins ignore until it's too late. They walk through a real 2025 case: how a mid-sized e-commerce platform lost 12 percent of checkout conversions because their monitoring dashboard showed CPU and RAM as green while storage latency was spiking. You'll learn what 'io...

In this episode, Lucas and Luna dive into the practical world of server backups using Borgmatic, a wrapper for the Borg backup tool. They walk through a real disaster scenario where a rogue script deleted a week's worth of customer transactions on a staging server, and how a Borgmatic backup saved the day. The discussion covers the key advantages of deduplication, encryption, and incremental backu...

Lucas and Luna make the case that structured server documentation—not just comments in config files, but a living runbook—is the single most impactful investment a sysadmin can make. They walk through a concrete example: a senior engineer at a mid-size SaaS company who spent two weeks building a Markdown-based runbook repository, and how it saved the team 40 hours during a critical PagerDuty escal...

Memory leaks are the ghosts of server administration: invisible until your OOM killer reaps a production process at 3 a.m. In this episode, Lucas and Luna walk through a real case from a mid-sized ad-tech company where a 12-line Node.js script silently consumed 32 GB over six days. They explain how to spot the early signs using /proc/meminfo, why RSS vs. USS matters, and the one tool (valgrind's m...

Episode 4 of Linux Server Admin looks at the single most common server authentication mistake: misconfigured SSH keys. Lucas and Luna walk through a real post-mortem from a fintech startup that left port 22 open with password authentication enabled for six months — not a breach, but a near-miss that triggered a full security audit. They break down SSH key anatomy, explain why 'ssh-keygen -t rsa -b...

Episode 3 of Linux Server Admin with Fexingo: Sysadmin, Bash, and Server Engineering. Lucas and Luna dive into a classic sysadmin mistake: letting logs fill up the root partition. Lucas explains how unbounded logging by a single chatty service took down a mid-size e-commerce platform for three hours last year, and why a dedicated log partition with proper rotation is the fix. He walks through part...

Lucas and Luna dive into the story of systemd, the init system that replaced SysVinit and Upstart across nearly every major Linux distribution. They walk through the specific boot-time problem systemd solved—parallel service startup versus the old sequential model—and unpack a concrete example: how a modern Fedora system boots from UEFI to a login prompt in under 10 seconds while an equivalent Sys...

In this first episode of Linux Server Admin with Fexingo, Lucas and Luna dive into a real-world incident at a mid-sized e-commerce company where a single typo in a deployment script — a missing dash in a rm command — took down the entire production fleet for 47 minutes. They walk through the timeline: what happened, how the team detected it via a sudden spike in 5xx errors, the immediate rollback...