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

Episode 39 of Linux Server Admin dives into Linux network namespaces for isolating server processes without full container runtimes. Lucas and Luna break down a real scenario: running a legacy monitoring agent that can't be containerized but must be network-separated from production traffic. They walk through creating a namespace, assigning a virtual Ethernet pair, and routing traffic through a dedicated bridge. Specific commands include 'ip netns add', 'ip link add veth', and iptables rules for NAT. The episode also covers debugging with 'nsenter' and 'ip netns exec', plus pitfalls like systemd integration and DNS resolution inside namespaces. By the end, listeners can isolate any process's network stack with five commands. The conversation includes a brief donation segment highlighting Fexingo's ad-free model at buy me a coffee dot com slash fexingo.

#Linux #Sysadmin #ServerEngineering #NetworkNamespaces #NetworkIsolation #Bash #TechPodcast #DevOps #Containerization #iptables #VethPair #ipCommand #nsenter #Systemd #ServerSecurity #Technology #FexingoBusiness #BusinessPodcast

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Lucas and Luna dive into Linux auditd, the powerful auditing subsystem that tracks security-relevant events on your servers. They walk through a real-world scenario: detecting unauthorized file access attempts using auditctl rules, interpreting ausearch output, and generating daily reports with aureport. The episode covers how to configure auditd without overwhelming your logs, common pitfalls like rule ordering and log rotation, and a practical example of monitoring /etc/shadow for suspicious reads. By the end, you'll know how to set up a simple but effective audit trail that helps catch intruders and meet compliance requirements. No fluff, just actionable sysadmin techniques.

#Linux #Sysadmin #Auditd #Security #ServerMonitoring #Compliance #Forensics #Auditctl #Ausearch #Aureport #FileIntegrity #Logging #Technology #FexingoTech #FexingoBusiness #BusinessPodcast #ITSecurity #LinuxSecurity

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Episode 37 of Linux Server Admin with Fexingo dives into control groups (cgroups) — the kernel feature that lets you limit CPU, memory, and I/O per process. Lucas and Luna walk through a real scenario: a runaway PHP-FPM pool consuming all server RAM on a shared hosting box. They explain how to set memory and CPU limits with cgroups v2, how to monitor usage with systemd-cgtop, and why this beats trusting nice values alone. Practical commands, real output, and a warning about the cgroup filesystem hierarchy. Perfect for sysadmins who want to stop one noisy neighbor from killing the whole server.

#Linux #ControlGroups #Cgroups #ResourceLimits #Sysadmin #ServerManagement #PHPFPM #MemoryLimit #CPUQuota #Systemd #CgroupsV2 #LinuxKernel #ServerPerformance #NoisyNeighbor #Technology #FexingoBusiness #BusinessPodcast #LinuxServerAdmin

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Episode 36 of Linux Server Admin with Fexingo dives into disk I/O benchmarking with FIO. Lucas and Luna walk through a real-world scenario: a database server showing intermittent slow queries, traced to unexpected I/O latency. They explain how to install FIO, construct a basic random-read/write test, interpret the output (IOPS, latency percentiles, bandwidth), and compare against expected performance for SSDs and HDDs. The episode covers why default test parameters can mislead, how to match workloads (e.g., 4K random vs. 64K sequential), and a simple three-run methodology for reliable baselines. Specific numbers include typical NVMe IOPS (500k+ random read), SATA SSD thresholds (80k IOPS), and how to spot controller saturation. No fluff—just practical steps to benchmark before tuning or blaming hardware.

#Linux #Sysadmin #ServerEngineering #DiskIO #FIO #Benchmarking #StoragePerformance #IOPS #Latency #DatabasePerformance #NVMe #SSD #ServerTuning #Technology #FexingoBusiness #BusinessPodcast #LinuxServerAdmin #PerformanceTuning

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Episode 35 tackles the hidden risk of inconsistent patching on Linux servers. Lucas and Luna walk through a real-world case: a mid-sized e-commerce company that suffered a 12-hour outage after applying kernel patches manually on a Friday afternoon. They break down why most sysadmins still rely on ad-hoc updates, how unattended-upgrades can backfire, and what a structured patch window looks like — including pre-patch snapshots, staged rollouts, and post-patch smoke tests. You'll learn the specific dangers of skipping patch automation: silent dependency drift, security gaps, and configuration drift across fleets. The episode also covers tools like cron-apt, yum-cron, and Ansible playbooks for patch orchestration, and why you should always test patches on a canary node first. Lucas and Luna don't just tell you to automate — they show you the cost of not doing it, from a real outage postmortem. By the end, you'll have a concrete checklist for building your own patch schedule, tailored to production workloads.

#LinuxServerAdmin #Sysadmin #PatchManagement #LinuxSecurity #ServerAutomation #BashScripting #Ansible #KernelUpdates #UnattendedUpgrades #DevOps #ProductionOutage #CanaryDeployments #Snapshots #CronJObs #RiskManagement #Technology #FexingoBusiness #BusinessPodcast

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Episode 34 of Linux Server Admin with Fexingo. Lucas and Luna walk through a real-world DNS failure that took down a staging environment for six hours. They explain how to use `dig`, `nslookup`, `systemd-resolved`, and `/etc/nsswitch.conf` to pinpoint the cause, and share a concrete fix using conditional forwarding in `systemd-resolved`. You'll also learn how to monitor DNS health with a simple custom script. Perfect for sysadmins who have ever stared at a blinking cursor wondering why `curl` hangs. Includes a quick note on how listener support keeps the show ad-free.

#Linux #DNS #Sysadmin #SystemdResolved #NetworkTroubleshooting #Dig #Nslookup #NsswitchConf #ResolvConf #BashScripting #ServerEngineering #Technology #FexingoBusiness #BusinessPodcast #DevOps #Infrastructure #OpenSource #CommandLine

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Lucas and Luna dive into Linux namespaces, the kernel feature that underpins container isolation but is often misunderstood. They explain the seven namespace types, show how a misconfigured namespace can leak host resources, and walk through a practical example using 'unshare' to create a minimal container. The hosts also discuss auditing namespace configurations with 'lsns' and 'nsenter', and why namespaces alone aren't enough without cgroups and seccomp. A must-listen for sysadmins who want to understand container security from the kernel up.

#Linux #Namespaces #ContainerSecurity #Sysadmin #Kernel #Docker #unshare #nsenter #lsns #cgroups #seccomp #Isolation #ServerEngineering #Technology #FexingoBusiness #BusinessPodcast #LinuxServerAdmin #Bash

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When your Linux server kernel panics, the typical sysadmin response is a hard reset — but that can destroy forensic evidence and risk data corruption. In this episode, Lucas and Luna walk through a step-by-step recovery procedure using the kernel's built-in SysRq key mechanism, the kdump crash-capture service, and crash utility analysis. They explain how to configure kdump to save a vmcore file on panic, how to use SysRq commands to trigger a controlled panic or sync disks before a forced reboot, and how to interpret common crash backtraces. Using a real-world example of a memory allocation failure in an ext4 filesystem driver, they show how crash analysis pointed to incompatible kernel module parameters — a fix that took one line in the module config file. Listeners learn a systematic approach to kernel panics that turns a server-down emergency into a diagnostic opportunity.

#Linux #Sysadmin #ServerEngineering #KernelPanic #SysRq #Kdump #CrashAnalysis #LinuxKernel #SystemRecovery #LinuxAdmin #FexingoBusiness #Technology #Podcast #ServerAdministration #LinuxTips #CrashDump #CentOS #Debugging

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Episode 31 of Linux Server Admin with Fexingo dives into the nightmare scenario: your Linux server's root filesystem is corrupted and won't boot. Lucas and Luna walk through a real rescue using the initramfs shell, manual fsck on a read-only root, chroot into the damaged system, and rebuilding the initramfs from inside the rescue environment. They cover when to use a live USB, how to mount proc/sys/dev in a chroot, and the critical step of checking your backup strategy before you need it. No fluff—just practical sysadmin skills for when the server won't come back.

#Linux #Sysadmin #ServerRescue #RootFilesystem #Initramfs #Fsck #Chroot #BootFailure #FilesystemCorruption #EmergencyRecovery #Ext4 #LiveUSB #RescueMode #BackupStrategy #Technology #ServerAdministration #FexingoBusiness #BusinessPodcast

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Episode 30 of Linux Server Admin with Fexingo tackles one of the most insidious server problems: a disk that's technically online but corrupting data silently. Lucas and Luna walk through a real case from a mid-size e-commerce company where a failing SATA drive went unnoticed for weeks, causing intermittent database corruption and mysterious application crashes. They explain how to detect the early warning signs using SMART attributes (specifically Reallocated Sector Count and Current Pending Sector), why standard monitoring often misses these, and how to set up a simple proactive alert with smartd and a systemd timer. The hosts also discuss read vs. write path failures, the risk of RAID-5 with large drives, and why you should never trust a single `fsck` result. By the end, you'll know exactly what to add to your server checklist to catch a quiet disk death before it takes down production.

#Linux #Sysadmin #ServerEngineering #SilentDiskFailure #SMART #DiskMonitoring #DataCorruption #smartd #systemd #RAID5 #HardDriveFailure #Storage #Bash #Technology #ServerAdmin #ITOps #FexingoBusiness #BusinessPodcast

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