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

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, they explain the difference between cgroups v1 and v2, show how to inspect cgroup hierarchies using systemd.slice units, and demonstrate persistent configuration via /etc/systemd/system.conf. The discussion also touches on how cgroups enable container runtimes like Docker and Podman. No fluff—just practical server management for sysadmins who need to keep noisy neighbors in check.

#CgroupsV2 #LinuxServer #Sysadmin #ResourceIsolation #Systemd #MemoryLimit #CPUAccounting #IOThrottling #ContainerRuntime #PHPFPM #OOMKiller #Technology #LinuxAdmin #ServerEngineering #Bash #FexingoBusiness #BusinessPodcast #Podcast

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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 when FUSE makes sense (and when it doesn't). Perfect for sysadmins who've wondered how tools like rclone, sshfs, or EncFS work under the hood or who need to extend a server's storage without patching the kernel. Includes a light-touch listener-support moment.

#Linux #Sysadmin #FUSE #FilesystemInUserspace #S3fs #CloudStorage #KernelModules #Userspace #ServerAdmin #Technology #DevOps #Storage #VirtualFileSystem #OpenSource #Tutorial #FexingoBusiness #BusinessPodcast #LinuxServerAdmin

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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, storing the passphrase with Clevis, and configuring a Tang server for unattended reboot. Luna probes the trade-offs—security vs. convenience—and they discuss real-world use cases like data-center compliance and cloud server encryption. No prior episodes have covered automated unlocking, making this a fresh angle for sysadmins looking to balance security with operational needs.

#Linux #ServerAdministration #DiskEncryption #LUKS #Clevis #Tang #NBDE #Systemd #Cryptsetup #Security #Encryption #DataCenter #LinuxSecurity #Sysadmin #Technology #FexingoBusiness #BusinessPodcast #ServerEngineering

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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 explain why certificate auth eliminates the need for manual authorized_keys management, simplifies onboarding and offboarding, and scales better than SSH keys for teams. The episode includes concrete commands, configuration file snippets, and a discussion of security trade-offs like CA compromise risk and certificate expiration. By the end, listeners understand how to implement SSH certificate authentication on their own Linux servers for more secure and manageable remote access.

#LinuxServerAdmin #SSH #CertificateAuthentication #Security #Sysadmin #Bash #ServerEngineering #Linux #SSHD #PublicKeyInfrastructure #DevOps #Infrastructure #Tech #FexingoBusiness #BusinessPodcast #Technology #ServerManagement #Cryptography

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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 synchronization status with chronyc, and a common gotcha with virtual machines and hardware clock drift. The episode includes a real-world example of a three-node server cluster that fell out of sync by 200 milliseconds and the cascading failures that followed. Practical commands and config snippets throughout. No fluff, just the stuff you need to keep your server clocks honest.

#Linux #ServerAdmin #Sysadmin #Chrony #NTP #TimeSynchronization #NetworkTimeProtocol #LinuxServer #Bash #ServerEngineering #Technology #Podcast #FexingoBusiness #BusinessPodcast #ITInfrastructure #DevOps #SystemAdministration #ServerManagement

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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 'OnBootSec', and troubleshooting with 'systemctl list-timers'. The episode explains why systemd timers offer better logging, dependency management, and integration with service units compared to traditional cron jobs. If you manage Linux servers and want more reliable scheduling with less overhead, this episode gives you a concrete, copy-paste-ready example you can adapt.

#Linux #ServerAdmin #Systemd #TimerUnits #Scheduling #CronReplacement #Ubuntu #NginxLogRotation #DevOps #Automation #Bash #Sysadmin #Technology #FexingoBusiness #BusinessPodcast #ITInfrastructure #ServerManagement #LinuxTips

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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_nodes and full_scans parameters, and measuring memory savings with ksmctl and /sys/kernel/mm/ksm. They also discuss security considerations—side-channel attacks like Rowhammer—and why KSM is a mixed bag for security-sensitive workloads. The episode closes with a practical decision framework: use KSM for development and CI/CD runners, but disable it for multi-tenant production or high-security environments. Includes a brief, natural support moment for the podcast's listener-funded model.

#KernelSamepageMerging #LinuxMemoryOptimization #KSM #ServerAdmin #Debian12 #Virtualization #Containers #RAMDeduplication #LinuxKernel #Sysadmin #MemorySavings #PerformanceTuning #Rowhammer #Security #LinuxServer #Technology #FexingoBusiness #BusinessPodcast

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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 concrete example: monitoring changes to /etc/shadow and /etc/passwd to catch privilege escalation attempts. They also discuss how auditd fits into compliance frameworks like SOC 2 and PCI-DSS. By the end, listeners learn how to build a lightweight auditing layer that runs alongside tools like Falco and Logwatch. Perfect for sysadmins who need to pass audits or investigate incidents without deploying heavy SIEM infrastructure.

#LinuxServerAuditing #Auditd #SecurityCompliance #Sysadmin #LinuxSecurity #Auditctl #Aureport #Ausearch #ServerHardening #Compliance #SOC2 #PCIDSS #FileIntegrityMonitoring #PrivilegeEscalation #Technology #Linux #FexingoBusiness #BusinessPodcast

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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 difference between chains, tables, and matches, and shares a minimal iptables script that secures a basic web server. Luna asks why iptables remains relevant alongside nftables, and they discuss migration strategies. Perfect for sysadmins who need practical iptables skills today.

#Iptables #LinuxFirewall #PacketFiltering #Netfilter #Sysadmin #ServerSecurity #LinuxNetworking #FirewallRules #StatefulFirewall #SSHHardening #Logging #IPTablesScripts #LinuxServer #Technology #BusinessPodcast #FexingoBusiness #SysadminTips #ServerEngineering

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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, and troubleshooting with radvdump. Luna asks about dual-stack priorities and when to disable IPv6 entirely. A practical episode for sysadmins moving beyond IPv4-only setups.

#IPv6 #LinuxServer #SystemdNetworkd #Networking #Sysadmin #SLAAC #DualStack #ServerAdmin #FexingoBusiness #BusinessPodcast #Technology #Podcast #NetworkConfiguration #IPv6Addressing #Radvdump #Sysctl #HomeLab #ServerEngineering

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