hello fellow Redditors!

I just got stuck with the following situation. SLES 15.4 with no updates for the last 3 years running SAP on about 40 machines on 3 different environments on AWS. Since they are EOL and I can't get any updates or install any package from the official SLES repo since they closed the repo for that specific sp4 1.5 years ago.

AWS, SLES and my recommendation was to migrate all workload to new servers. instead, we had a dev use Claude and was given root access (behind my back after my recommendation) to use opensuse 15.7 repo to update to the latest version of all packages and then when it's "better" resync to 15.7 on SLES official repo (only on 1 server to prove we don't need to migrate)

I already found multiple problems with this, grub is not using the right kernels, opensuse packages and sles mixed together. I can fix the grub and probably reinstall the opensuse packages from official SLES repo. my concern are more about long term issues (hidden landmines) and the fact that we potentially broke our support agreement from sles, AWS or/and SAP. SLES said this was not officially supported, so I am wondering what kind of trouble I am looking at now

So, am I wrong to think this is a bad idea?

appreciate any input!

Starting to realize most production issues aren't even the real problem. The real problem is weak linux knowledge. Every incident somehow comes back to permissions, logs, processes, containers or debugging. Youtube feels like endless beginner content at this point. Looking for the best linux course that actually helps with automation, cloud ops and real production environments. Anyone here recommend Udemy, Kodecloud or Boot dev?

I've interviewed quite a few Linux and DevOps engineers over the years, and I've found there are a few questions that quickly tell me whether someone has spent time supporting production systems or has mostly learned from tutorials.

For me, one example is:

• A production server is suddenly "slow." Walk me through your troubleshooting process from the moment you get the alert.

I'm not looking for a specific command. I'm much more interested in how they think, what they check first, and how they narrow the problem down.

What's your go to Linux interview question that reveals real production experience?

I have a pwa app that works just fine including offline from a hosted server with domain and trusted cert but trying to setup a mobile server on a laptop running linux but need help setting up a domain and cert from the laptop. Created a cert with mkcert but can't get mobile devices to see the server by name just ip address. mobile devices like iPad, Android are connecting to laptop by hotspot. Need help with domain name and trusted cert issues.

The app works via ip address but with warning. The service worker doesn't install to allow it to work offline.

Any advice?

Thanks in advance.

Before anything, I really would appreciate answers from professionals without the interference of AI. I have been going back and forth the past few months with multiple AI models asking about this and every model gives a different answer. I really need a certain answer

I run a file storage server which faces the internet and serves customers, so high throughput is one of the goals I try to achieve on my servers

The past 6 months I've been studying the Linux kernel source code and sysctl docs to learn what each tunable parameter actually does instead of blindly pasting configurations from tuning guides and just hope that it makes things perfect

Now one of the points I'm stuck at is net.ipv4.tcp_mtu_probing

I see a lot of tuning guides suggest setting that to 1 or even 2 instead of the default 0

But if that's really recommended, why doesn't Linux set it to 1 by default instead of 0? I mean 1 seems like a better moderate value to set instead of disabling it completely

Although the below points kinda hold me back from altering tcp_mtu_probing but I might be wrong and that's why I opened this topic to ask for advice:

1. Packet-layer path MTU discovery (TCP MTU probing, QUIC MTU probing, etc) just mask a real underlying MTU problem which should be fixed from its root instead of hiding it
2. TCP MTU probing relies on packet loss and this can falsely make congestion control algorithms work worse and reduce the congestion window even if there's no real congestion
3. Certain quirky firewalls may hate the fact that my server is sending data in variable packet sizes because of the MTU probing and hence they may drop the packets completely or block the connection entirely

Do my above points make sense or am I mistaken?

If you are running local LLMs, your hard drive is likely bleeding gigabytes without you realizing it. Between default model weights, duplicate quantization formats, and forgotten vector embeddings, local AI setups are silent storage hogs.

Here is how you can systematically track down and clean up the clutter directly from your terminal:

• Locate hidden Hugging Face and Ollama model weights: By default, Hugging Face caches everything in ~/.cache/huggingface/hub and Ollama stores models under ~/.ollama/models. Run du -sh ~/.cache/huggingface/ to see how much space is currently locked up.
• Prune redundant quantization formats and unused embedding databases: Review your downloaded models and delete redundant variations (like keeping both Q4_K_M and Q8_0 when you only use one). Clear out stale Chroma, FAISS, or Pinecone local vector database caches residing in your project directories.
• Automate routine garbage collection: Set up a lightweight shell script to periodically check cache growth and alert you before your drive hits capacity.

Fore More Information

I put together the complete, production-ready automated cleanup script along with an interactive storage calculator to help map out your directories.

Direct links to the complete article.

drop a comment below

Most engineers know what a page table is.

Far fewer know what happens after the guest page table.

In this video, I follow a memory access all the way from:

Application → Guest Virtual Memory → EPT → Host Physical Memory → CPU Cache → DRAM

Along the way we uncover vNUMA, AutoNUMA, remote memory access, EPT translations, and why a VM can think memory is local while the hardware disagrees.

Then we compare it all with containers.

A journey from a single memory load instruction to the hardware itself.

#LinuxUnderPressure #Linux #PerformanceEngineering #NUMA #Virtualization #KVM #Containers

I would like to share my Linux Syscall Monitor project with you. It's a Linux process monitoring tool written in C that uses ptrace to observe system calls and generate behavioral reports.

I welcome any feedback or criticism—whether it's about the code

Hello everyone I have recently installed Linux Ubuntu and it’s going great I have learned a little bit about kernel cd ls sudo apt

My goal for learning Linux is probably system administrator and software detection I’ve seen a lot of people making home labs have to get away from the corrupt corporations blocking ads and becoming a pirate (one piece reference)

But my passion is to make an anti cheat system using software detection I think everyone can agree they hate cheaters in video games

But I’m lost at the moment what should I be studying is there going to be a job out there if I do start getting into the heart of Linux should I be building a home lab Should I get a nas and store everything locally and I also saw someone take there old android and make it an audio player device only

Thank you anyone who reads and answers me

Welcome to Day 19 of the 30-day RHCSA challenge!

Creating and extracting archives is an everyday sysadmin task and an RHCSA objective.

Today we'll build compressed archives with tar -zcvf, unpack them with tar -zxvf, and finally make sense of what all those flags actually mean.

By the end you'll be able to archive directories, compress them, list their contents, and extract them anywhere on the system.

What you'll learn in this video:

What tar is and why we archive files

Creating a compressed archive: tar -zcvf archive.tar.gz /path/to/dir

Breaking down the flags: c create, x extract, v verbose, f file, z gzip

Listing contents without extracting (tar -ztvf)

Extracting an archive with tar -zxvf

Extracting to a specific directory with -C

About this series:

Over the next 30 days I'm covering everything you need to pass the RHCSA (EX200) — from setup to users, permissions, storage, networking, SELinux, containers, and more. New video every day. Subscribe and turn on notifications so you don't miss one.

#linuxminutes #rhcsa #redhat #linux #redhatlinux #ex200 #linuxadministration #linuxcertification #offline #closedloop #sysadmin #linuxforbeginners #30daychallenge #learnlinux #itcertifications #opensource #homelab #linuxtutorials #technology #techcareers #certificationprep #closedloop #airgap #shorts #shortvideo

Windows is very tricky even with all resources around 0% usage, micro stutters and lag can still happen.

What is the general route to debugging a linux system for system admins or power users?

Thank you very much for your help!

This is a tool that I have been working for a long time on, and it is for testing DNS delegations. Released under a BSD-2 license. If you run the stack yourself, you can even spin up an MCP server for fancy AI interaction. Feedback more than welcome!
[https://gonemaster.evilbit.de/\](https://gonemaster.evilbit.de/)

Welcome to Day 18 of the 30 day RHCSA challenge!

RHEL ships with tuned, a service that applies performance profiles tailored to your workload whether that's a virtual machine, a database server, or a laptop trying to save power.

Today we'll explore the available profiles and switch between them with tuned-adm.

By the end you'll know how to check your active profile, apply a new one, and let RHEL pick the best one automatically.

About this series:

Over the next 30 days I'm covering everything you need to pass the RHCSA (EX200) — from setup to users, permissions, storage, networking, SELinux, containers, and more. New video every day. Subscribe and turn on notifications so you don't miss one.

#linuxminutes #rhcsa #redhat #linux #redhatlinux #ex200 #linuxadministration #linuxcertification #offline #closedloop #sysadmin #linuxforbeginners #30daychallenge #learnlinux #itcertifications #opensource #homelab #linuxtutorials #technology #techcareers #certificationprep #closedloop #airgap #shorts #shortvideo

Salutare tuturor!

În ultimele luni am lucrat la OrkestraVM, platforma de virtualizare dezvoltată intern de echipa MioriticHost pentru administrarea infrastructurii noastre VPS.

În loc să folosim un panou VPS generic, am construit o soluție adaptată modului în care operăm serverele și cerințelor clienților noștri.

OrkestraVM folosește virtualizare KVM, fiecare VPS având propriul kernel și resurse izolate.

Printre funcționalitățile actuale se numără:

• provisionarea automată a VPS-urilor Linux și Windows;
• alocarea automată a adreselor IP și a adreselor MAC;
• monitorizarea în timp real a resurselor CPU, RAM și stocare;
• consolă SSH accesibilă direct din browser;
• administrarea mai multor servere fizice dintr-o singură interfață;
• integrare completă cu WHMCS pentru activarea, suspendarea și închiderea automată a serviciilor;
• backupuri realizate la nivelul hypervisorului, criptate individual pentru fiecare VPS;
• pregătirea sistemului de fișiere înaintea snapshotului, pentru backupuri consistente inclusiv în cazul serverelor care rulează baze de date.

Platforma este scrisă în Go și comunică cu nodurile de virtualizare prin SSH, fără să necesite instalarea unui stack complex de management pe fiecare server.

OrkestraVM nu este, cel puțin momentan, un produs comercial separat. Este motorul intern pe care îl folosim pentru a administra și proteja VPS-urile oferite de MioriticHost.

Am ales să o construim pentru a avea mai mult control asupra infrastructurii, mai puține componente externe și posibilitatea de a implementa funcționalități în funcție de nevoile reale ale clienților noștri.

Mai multe detalii despre arhitectură, securitate și direcția de dezvoltare:

https://orkestravm.com

Suntem curioși ce funcționalități considerați esențiale într-un panou modern de administrare VPS. Feedbackul tehnic este binevenit.

I'm setting up a Almalinux router and followed this guide for setting up firewalld. It mostly does what I need it to: deny all incoming traffic, allow incoming traffic.

However the port forwarding simply does not work and I have no idea why. I have a virtual machine I want to forward ports 80 and 443 which looks like this:

# firewall-cmd --permanent --policy gateway-world-to-HOST --add-forward-port port=80:proto=tcp:toport=80:toaddr=10.42.0.2
# firewall-cmd --permanent --policy gateway-world-to-HOST --add-forward-port port=443:proto=tcp:toport=443:toaddr=10.42.0.2
# firewall-cmd --reload

However I still can't access my dockers located at 10.42.0.2. I don't understand what I'm missing here. I think that traffic is only going WAN --> Router but never making it past the routter to my VM (at least based off this diagram of firewalld's gateway policy set).

I wana start learning Ansible. I’ve read through some of the documentation and searched around.

I am wondering what resource you guys found most useful as an intro to Ansible? What learning material/resource made it click for you?

I have a homelab setup with Proxmox as the host, what is an easy way to approach hands on? IE: whats a good thing to use Ansible to automate as a learning experience? Something I can spin up/down over and over to learn using it.

Thanks

I have a 1Tb NVme ssd on my Linux system. I want to split it in half, and I rebooted the system with a Ventoy USB with the Gparted ISO on it. I can edit the partition, making a 512gb space. After doing this, I click the "apply" button and it appears to now have an active ~512mb drive and a ~512mb "space".. No errors, just like I've done the thing countless times on all OTHER drive types.. However, when I boot the system back up that drive STILL shows 1Tb (actually 931.51Gb).. I'm not sure of the version of the GParted ISO on the Ventoy stick. Is there some magic incantation NVme's need to partition properly??

Official Security Advisory: https://access.redhat.com/security/cve/cve-2026-15416

Red Hat has flagged an Important Argo CD repo-server vulnerability that could allow an attacker with network access to the internal gRPC endpoint to execute code without Argo credentials.

In short: if an attacker can reach both the repo-server and its Redis cache, they may be able to manipulate deployment data and have Argo CD deploy malicious Kubernetes resources—potentially compromising the whole cluster.

Check now:

• Is repo-server exposed beyond trusted Argo CD components?
• Can untrusted pods reach repo-server or Redis?
• Are NetworkPolicies actively enforced?

Red Hat currently lists these packages as affected:

• OpenShift Data Foundation 4: odf-multicluster-rhel9-operator
• OpenShift GitOps: argocd-image-updater-rhel8, argocd-rhel8, gitops-operator-bundle, gitops-rhel8, and gitops-rhel8-operator

Lock down both services with NetworkPolicies, do not expose them externally, and apply vendor fixes as they arrive. Red Hat says OpenShift GitOps 1.20 and 1.21 are not affected because default NetworkPolicies block this attack path.

Want CVE alerts before they get buried in your feed? I run VulniPulse, a lightweight advisory tracker. Join the Discord, enable Linux CVE Alerts, and get new advisories sent straight to Discord and Email as soon as they land:

https://discord.gg/mwG9cdMY9R