#learnbyfixing — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #learnbyfixing, aggregated by home.social.
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New scenario released!
A new marketing campaign is expected to drive a sharp increase in traffic to your infra.
A legacy pod may not have enough CPU to handle the load.
The app is business-critical.
You cannot restart it.You tried "kubectl edit", but you got the classic error:
"Forbidden: pod updates may not change fields other than ..."Can you double the current CPU resources for the pod with zero downtime?
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A developer on your team suggests this approach:
1. Copy a file with an API key into the Docker image during build.
2. Use it to set up the app.
3. Delete the file in a later step.Their conclusion: "The file won’t be in the final Docker image, so it’s safe."
You disagree. All layers of a Docker image are kept, so the API key is still there.
Your challenge: Find the API key hidden in the Docker image.
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Struggling with Docker issues? This new troubleshooting roadmap can help:
https://www.learnbyfixing.com/roadmaps/docker/
It brings together practical guides and structured skill paths to sharpen your Docker debugging abilities.
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New guide released: Namespaces and nsenter
It starts from a simple challenge, but every time you solve it, a new constraint is added, and you have to figure out another way to crack it.
The challenge is this: List all listening TCP ports (IPv4) inside a container.
It includes constraints such as using distroless containers and Docker rootless mode.
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After a sudden reorganization, your team has just inherited a legacy Docker image with no docs.
The container starts, but no ports are exposed and the logs are unhelpful.
Right now, the application running inside the container is completely inaccessible.At first, this feels like a quick fix… until you hit the constraints:
- Distroless image
- Rootless Docker setup
- No sudo accessCan you find and expose the port?
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A Docker container can't connect to its own DB, but why?
- DNS resolution?
- Network connectivity?
- Rootless Docker misconfig?
- Or all three at once?Most container issues aren’t where you think they are.
New hands-on scenario to debug this exact mess:
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Most people don't fail at learning Linux troubleshooting… They just don't know what to learn next.
Check out this Linux Troubleshooting Roadmap if you want to:
- Improve your Linux troubleshooting skills
- Stop jumping between random topics
- Follow a clear, practical path -
New guide released: Signals in Docker
- Why PID 1 is important inside a container
- docker stop vs docker kill
- How to make containers shut down gracefully
- How to send signals to containers -
New scenario released! 🚀
An app was set up locally using Docker Compose... but it doesn't start.
It has 3 services: proxy, app and database.
Can you make it work?
https://www.learnbyfixing.com/scenarios/19/
Happy fixing!
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New scenario released! 🚀
You tried to start a containerized app, but it doesn't run.
A colleague says it works on their laptop.
Can you make it run without changing the app's code?
https://www.learnbyfixing.com/scenarios/18/
Happy fixing!
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New scenario released! 🚀
A Docker image was built to deploy an app to production… but there’s a problem.
It's over 1 GB.
Your mission: optimize its size to be under 20 MB.
Can you fix it?
https://www.learnbyfixing.com/scenarios/17/Happy fixing!
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🚀 Big Update: From Tutorials to Real Challenges.
Our labs are now real challenges, featuring:
- A "Check Solution" button to instantly validate your work.
- Optional hints if you get stuck.
- Full solution reveal when you're ready.Less: "Follow these steps".
More: "Something is broken. Fix it."Because that’s what real-world scenarios look like.
Ready to take on real DevOps challenges?
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Instant DevOps Labs: Hands-On & Free! 🚀
Get 15 minutes of real Linux environment practice with genuine scenarios.
No signup. No email. No credit card required.
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New features are here! 🚀
We’ve just launched two highly requested improvements:
- Skill-level filtering in Scenarios: find the right challenges for you.
- GitHub login support: seamless access using your GitHub account.Ready to dive in and get hands-on? https://www.learnbyfixing.com/scenarios/
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New scenario released! 🚀
Your challenge: reload the configuration of a containerized app without restarting the Docker container.
Sounds easy? Not so much when the container uses a distroless image (no shell, no debugging tools).
This scenario walks you through how to do it: https://www.learnbyfixing.com/scenarios/16/
Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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We have just expanded the Environment Variables guide to include their use in Docker containers:
https://www.learnbyfixing.com/guides/environment-variables/
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers #EnvironmentVariables
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New scenario released! 🚀
You have a verbose Docker container.
Your challenge: make it log ERROR messages only without modifying the image.In this scenario, you’ll learn how to control container behavior using environment variables.
Sharpen your Docker skills and try it now:
https://www.learnbyfixing.com/scenarios/15/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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New scenario released! 🚀
You have a verbose Docker container.
Your challenge: make it log ERROR messages only without modifying the image.In this scenario, you’ll learn how to control container behavior using environment variables.
Sharpen your Docker skills and try it now:
https://www.learnbyfixing.com/scenarios/15/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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New scenario released! 🚀
You have a verbose Docker container.
Your challenge: make it log ERROR messages only without modifying the image.In this scenario, you’ll learn how to control container behavior using environment variables.
Sharpen your Docker skills and try it now:
https://www.learnbyfixing.com/scenarios/15/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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New scenario released! 🚀
You have a verbose Docker container.
Your challenge: make it log ERROR messages only without modifying the image.In this scenario, you’ll learn how to control container behavior using environment variables.
Sharpen your Docker skills and try it now:
https://www.learnbyfixing.com/scenarios/15/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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New scenario released! 🚀
You have a verbose Docker container.
Your challenge: make it log ERROR messages only without modifying the image.In this scenario, you’ll learn how to control container behavior using environment variables.
Sharpen your Docker skills and try it now:
https://www.learnbyfixing.com/scenarios/15/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #Docker #Containers
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New free guide released: System calls and strace! 🚀
Do you want to troubleshoot Linux like a pro? Our latest free guide shows you how to inspect system calls using strace, a must-have tool for every SysAdmin, SRE and DevOps engineer.
https://www.learnbyfixing.com/guides/system-calls-and-strace/
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
Port already taken? But which one?
In this scenario, you’ll learn how to:
- Identify which port a program needs to listen on.
- Track down the process that's already listening on that port.Level up your Linux troubleshooting skills and dive in now!
https://www.learnbyfixing.com/scenarios/14/Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
Having the config file for a program is not enough. You also need to put it in the right place so that the program can find it. But it's not that easy when you don't know where the program is looking for its config file!
Check it out and level up your troubleshooting skills: https://www.learnbyfixing.com/scenarios/13/
Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
Having the config file for a program is not enough. You also need to put it in the right place so that the program can find it. But it's not that easy when you don't know where the program is looking for its config file!
Check it out and level up your troubleshooting skills: https://www.learnbyfixing.com/scenarios/13/
Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
Having the config file for a program is not enough. You also need to put it in the right place so that the program can find it. But it's not that easy when you don't know where the program is looking for its config file!
Check it out and level up your troubleshooting skills: https://www.learnbyfixing.com/scenarios/13/
Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
Having the config file for a program is not enough. You also need to put it in the right place so that the program can find it. But it's not that easy when you don't know where the program is looking for its config file!
Check it out and level up your troubleshooting skills: https://www.learnbyfixing.com/scenarios/13/
Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #syscalls #strace
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New scenario released! 🚀
https://www.learnbyfixing.com/scenarios/12/
Imagine you don't know how to quit vi / vim / neovim .
Figure out how to exit without using any vi commands.Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #vi #vim #neovim
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New scenario released! 🚀
https://www.learnbyfixing.com/scenarios/12/
Imagine you don't know how to quit vi / vim / neovim .
Figure out how to exit without using any vi commands.Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #vi #vim #neovim
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New scenario released! 🚀
https://www.learnbyfixing.com/scenarios/12/
Imagine you don't know how to quit vi / vim / neovim .
Figure out how to exit without using any vi commands.Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #vi #vim #neovim
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New scenario released! 🚀
https://www.learnbyfixing.com/scenarios/12/
Imagine you don't know how to quit vi / vim / neovim .
Figure out how to exit without using any vi commands.Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #vi #vim #neovim
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New scenario released! 🚀
https://www.learnbyfixing.com/scenarios/12/
Imagine you don't know how to quit vi / vim / neovim .
Figure out how to exit without using any vi commands.Happy fixing!
#LearnByFixing #Linux #DevOps #SRE #Sysadmin #vi #vim #neovim
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We are excited to announce the official launch of Learn by Fixing! 🚀
Ready to try it? https://www.learnbyfixing.com
Happy fixing!
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We are excited to announce the official launch of Learn by Fixing! 🚀
Ready to try it? https://www.learnbyfixing.com
Happy fixing!
-
We are excited to announce the official launch of Learn by Fixing! 🚀
Ready to try it? https://www.learnbyfixing.com
Happy fixing!
-
We are excited to announce the official launch of Learn by Fixing! 🚀
Ready to try it? https://www.learnbyfixing.com
Happy fixing!
-
We are excited to announce the official launch of Learn by Fixing! 🚀
Ready to try it? https://www.learnbyfixing.com
Happy fixing!