Over the past two years, I’ve been running my websites and various projects using Docker containers, a decision that has mostly been a smooth and efficient experience. However, as they say, “smooth seas do not make skillful sailors,” and my recent journey with Docker has taught me that the Docker Learning curve is easy to start, but be ready for some valuable lessons about resilience, problem-solving, and the importance of proper setup.
Docker Learning Curve: Running 70+ Containers Without Issues
At one point, I had an impressive 70 Docker containers running simultaneously. This setup allowed me to manage multiple websites, services, and personal projects with ease. Docker’s ability to isolate environments and scale resources made it an invaluable tool for my workflow.
I have a decent home server that I configured running the apps and websites. I like to keep my DBs and Backups both on their own separate servers.
I never encountered a major issue during this time, until disaster struck.
The First Disaster: Docker Fails and I Have No Idea What to Do
One day, without warning, Docker began failing on me. As a relative newcomer to Docker, I was completely clueless about how to diagnose or fix the problem. After spending hours researching online and following advice from AI tools, I decided to take drastic measures: I deleted and reinstalled Docker.
While this approach seemed to resolve the immediate issue, it came with a significant consequence—I blew away my entire Docker network configuration. This meant that while core services eventually came back online, reconstructing my setup was a time-consuming process. To make matters worse, some of my projects were still in limbo as I waited to create proper docker-compose files.
The Second Challenge: Running Out of Disk Space
Just when I thought things had settled down, another issue arose—a critical lack of disk space on my system. A quick check revealed that the /mnt/user directory was nearly full:
Filesystem Size Used Avail Use% Mounted on
/dev/md0 232G 224G 8.0G 97% /
I soon realized that Docker might be configured to store data on this disk, which could complicate things further. To address the issue, I turned to docker system prune, a command designed to remove unused resources.
QUICK WIN: Prune Docker Everything (Safe & Instant)
Here’s what I did:
docker system prune -a --volumes -f
Flags Explained:
-a: Removes all unused images, not just dangling ones. With 30+ containers running, many of these images were outdated and unnecessary.--volumes: Deletes all volumes not attached to a running container. Runningdocker volume lsshowed that only 10 volumes were in use; the rest were orphaned.-f: No confirmation prompt—this command is irreversible.
The process took some time, but it was worth it:
- Deleted 6 containers
- Removed 9 networks
- Erased 2 volumes
- Freed up disk space by removing over 150 images
After running the command, the filesystem report showed significant improvement:
- Available space increased from 8 GB to 84 GB.
- Used space decreased from 224 GB to 131 GB, freeing up approximately 93 GB.
Filesystem Size Used Avail Use% Mounted on
/dev/md0 232G 131G 84G 62% /
However, this fix wasn’t without its consequences. Some of my sites didn’t function as expected afterward, and I’m still working on identifying and resolving these issues.
Lessons Learned: What I Would Do Differently
Reflecting on this experience, here are a few key takeaways:
- Regular Maintenance: Running
docker system pruneperiodically could have prevented the disk space issue altogether. - Backup and Documentation: Having backups of my Docker configurations and networks would have saved me significant time during recovery.
- Proper Setup from the Start: Ensuring that Docker is configured to use a dedicated storage directory (and monitoring its usage) could prevent future crises.
Moving Forward: A New Approach
Now, I’m in the process of reworking my server setup and ensuring that Docker is properly configured. If you’re interested in learning more about this ongoing project, check out my previous post: Navigating Server Challenges: My Docker Dilemma and Hardware Overhaul.
In the meantime, I’m focusing on:
- Creating proper
docker-composefiles for all my projects. - Implementing a regular maintenance schedule to avoid future issues.
- Exploring options for better disk management and monitoring.
Conclusion: Embracing the Learning Curve
While my Docker journey has been rocky at times, it’s also been incredibly educational. Every challenge I’ve faced has taught me something new about containerization, system administration, and problem-solving.
If you’re new to Docker, or even if you’ve been using it for years, remember that setbacks are part of the learning process. Take precautions, document your work, and always have a backup plan. And most importantly? Don’t hesitate to reach out to the community or seek advice when you’re stuck.
After all, we’re all in this together!
Have you had similar experiences with Docker? Share your stories, tips, or lessons learned in the comments below, I’d love to hear from you!