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

Episode 139 dives into LVM thin provisioning on Linux servers — a storage strategy that lets you over-commit disk capacity without wasting physical space. Lucas walks through creating a thin pool, provisioning logical volumes, enabling auto-extension, and leveraging snapshots for fast dev/test rollbacks. Luna challenges the trade-off: what happens when the pool fills up? They also cover monitoring with lvs and dmeventd, and a real-world case of a CI pipeline that reclaimed 60% of its allocated storage. If you manage server storage for containers or VMs, this episode gives you a concrete configuration to try today.

#LVM #ThinProvisioning #LinuxStorage #ServerAdmin #Sysadmin #LogicalVolumeManager #ThinPool #Snapshots #StorageEfficiency #DataManagement #Overcommit #Dmeventd #LinuxServer #DevOps #ContainerStorage #Technology #FexingoBusiness #BusinessPodcast

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User namespaces are a powerful Linux kernel feature that lets containers run as ‘root’ inside their namespace while actually running as an unprivileged user on the host. In this episode, Lucas and Luna walk through a real-world scenario: an attacker who compromises a containerized web app and tries to escape to the host. With user namespace mapping, the attacker’s root privileges inside the container are worthless outside it. They explain how UID 0 inside maps to UID 100000 outside, why this breaks privilege escalation, and how to configure user namespaces with Podman and runc. They also discuss the trade-offs: not all system calls are sandboxed, and filesystem permissions get tricky. Practical takeaways include how to verify mappings, how to avoid common misconfigurations, and why user namespaces are not a silver bullet but a critical layer in defense-in-depth. A must-listen for any engineer hardening container hosts.

#LinuxServer #Sysadmin #ContainerSecurity #UserNamespaces #Podman #Docker #KernelSecurity #PrivilegeEscalation #DefenseInDepth #UIDMapping #RootlessContainers #ContainerEscape #SecurityHardening #FexingoBusiness #BusinessPodcast #Technology #LinuxAdmin #ServerEngineering

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In this episode, Lucas walks through setting up Prometheus version 2.53 and Node Exporter on a freshly provisioned Ubuntu 24.04 server. He demonstrates how to install the binaries from the official tarball, configure the prometheus.yml to scrape localhost:9100 every 15 seconds, and verify metric ingestion using the expression browser. Luna asks about the pull model versus push-based tools, and Lucas highlights the value of historical data for troubleshooting night-time anomalies. They also touch on writing a simple alerting rule for CPU usage above 80 percent. The episode closes with a reflection on why open-source monitoring beats SSH-based diagnosis for multi-server environments.

#Linux #Sysadmin #Prometheus #NodeExporter #Monitoring #DevOps #ServerAdmin #OpenSource #Metrics #Performance #Alerting #CPU #Memory #Disk #Network #Fexingo #TechnologyPodcast #LinuxServer

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When your Linux web server stalls for five seconds on every other request, where do you start? This episode walks through a real debugging session using strace and ltrace to uncover a hidden file-lock bottleneck. Lucas and Luna trace system calls and library calls in real time, showing how a single read operation on a shared config file turned a fast Nginx server into a crawl. You'll learn the practical difference between strace's -p and -c flags, how to read call output without drowning in data, and when ltrace's library-level view reveals what strace misses. By the end, you'll have a repeatable process for attaching to a misbehaving process, filtering the noise, and pinpointing the exact kernel interaction causing the delay. Perfect for sysadmins who manage production Linux servers and want to retire the guess-and-reboot workflow.

#LinuxServerAdmin #Sysadmin #Strace #Ltrace #Debugging #Performance #ServerTroubleshooting #Bash #Technology #FexingoBusiness #BusinessPodcast #Linux #SystemCalls #FileLock #WebServer #ProcessTracing #Engineering #ServerAdmin

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In this episode of Linux Server Admin, Lucas and Luna walk through the practical steps of encrypting a server's disk using LUKS (Linux Unified Key Setup). They cover partitioning an encrypted LVM volume, creating a LUKS container, unlocking it at boot via a keyfile stored on an initramfs, and managing passphrases. The discussion includes performance considerations, backup of LUKS headers, and integrating with systemd for automatic unlocking. Perfect for sysadmins securing sensitive data without third-party tools. The hosts also touch on how small recurring listener support keeps the show ad-free and focused on real-world server engineering.

#Linux #ServerAdministration #LUKS #DiskEncryption #Cryptsetup #LVM #KeyManagement #Sysadmin #Security #Cryptography #DataProtection #Systemd #Initramfs #FexingoBusiness #BusinessPodcast #Technology #ServerHardening #Compliance

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Episode 134 digs into SELinux — the mandatory access control layer most sysadmins avoid. Lucas and Luna break down how SELinux works, why it matters for application confinement, and walk through a real example: locking down an Apache web server with targeted policies. They cover booleans, contexts, and audit logs, plus common pitfalls like confined vs unconfined domains. If you've never touched SELinux because it's 'too complex', this episode gives you the practical starting point to secure your Linux server workloads without losing your mind.

#SELinux #LinuxServer #Sysadmin #Security #AccessControl #MandatoryAccessControl #Apache #WebServer #PolicyManagement #AuditLog #CentOS #RHEL #ApplicationSecurity #KernelSecurity #Fexingo #Technology #FexingoBusiness #BusinessPodcast

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In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the art of swap configuration on modern Linux servers. They debunk the old 'twice the RAM' rule, explain why SSDs change the calculus, and walk through practical adjustments like setting vm.swappiness to 10 for database workloads. The conversation also covers compressed swap options like zram and zswap, and how to monitor swap pressure with tools like sar and vmstat. A must-listen for any sysadmin managing memory-constrained or high-availability servers.

#LinuxServerAdmin #Sysadmin #SwapTuning #MemoryManagement #Zram #Zswap #Swappiness #LinuxPerformance #ServerEngineering #Technology #FexingoBusiness #BusinessPodcast #Podcast #LinuxTips #NixOS #SSDPerformance #OOMKiller #KernelTuning

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Episode 132 of Linux Server Admin tackles systemd service hardening. Lucas and Luna break down a real-world case: a misconfigured Apache server that exposed /etc/shadow due to missing sandboxing. They walk through systemd's security directives—PrivateTmp, ProtectSystem, NoNewPrivileges, and more—and discuss common pitfalls like breaking legitimate functionality. Practical tips for locking down services without breaking your apps. Perfect for sysadmins running modern Linux servers.

#LinuxServer #Systemd #Security #Hardening #Sysadmin #ServerEngineering #Apache #PrivateTmp #ProtectSystem #NoNewPrivileges #CapabilityBoundingSet #SystemCallFilter #ReadOnlyPaths #InaccessiblePaths #LinuxSecurity #FexingoBusiness #BusinessPodcast #TechPodcast

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In this episode of Linux Server Admin, Lucas and Luna dive into cgroups v2, the modern kernel feature for limiting CPU and memory usage of processes. They explain why traditional tools like nice and ulimit fall short, and demonstrate how to use systemd's drop-in files to apply resource constraints to any service. Using a real-world example of a memory-hungry database process, they show how to set MemoryMax, CPUQuota, and IOWeight, and how to verify limits with systemd-cgtop. The episode also covers pitfalls like forgetting to set Delegate=true for custom cgroup hierarchies, and how cgroups v2 integrates with container runtimes like Podman. Practical, battle-tested advice for sysadmins managing shared or high-density servers.

#ControlGroups #cgroupsv2 #LinuxServer #Systemd #ResourceLimits #CPUQuota #MemoryMax #Sysadmin #ServerAdmin #LinuxKernel #Podman #ContainerLimits #Technology #LinuxAdmin #Bash #SystemdDropIn #FexingoBusiness #BusinessPodcast

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Lucas and Luna dive into perf, the Linux profiling tool, with a real production scenario: a web server experiencing high CPU latency. They walk through capturing performance data using perf record, analyzing hot functions with perf report, and visualizing call stacks with flamegraphs. You'll learn how to pinpoint the exact function consuming CPU cycles—whether it's a Lua script in Nginx or a kernel driver. The episode covers sampling frequency, call-graph modes, hardware counters like instructions per cycle, and syscall tracing with perf trace. By the end, you'll have a repeatable workflow for diagnosing CPU bottlenecks, applicable to any Linux server running kernels 5.x and above. This is Episode 130 of Linux Server Admin with Fexingo, and includes a brief behind-the-scenes on how listener support keeps the show ad-free. Perfect for sysadmins, DevOps engineers, and anyone who manages production servers and wants to move beyond guesswork.

#LinuxServerAdmin #FexingoBusiness #TechnologyPodcast #Linux #Perf #CPUProfiling #PerformanceMonitoring #Flamegraph #ServerOptimization #KernelTuning #Sysadmin #DevOps #Nginx #ProfilingTools #SystemAnalysis #PerformanceDiagnostics #LinuxPerformance #Episode130

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