Container Basics On Linux (Namespaces/Cgroups)

Stop letting your containerized processes leak memory all over the host

🧩 The Challenge

You’ve finally deployed that microservice only to realize it’s gobbling up every spare byte of RAM on your server. I’ve spent way too many nights debugging why my host’s kernel decided to just nuke my ssh session because a random container turned into a memory hog.

💡 The Fix

Use cgroups to put that container on a strict diet so it can’t steal resources from the rest of the OS. You really want a hard limit that stops it cold before it hits your swap space.

echo 512M > /sys/fs/cgroup/memory/my_service/memory.limit_in_bytes
echo $$ > /sys/fs/cgroup/memory/my_service/tasks

⚙️ Why It Works

By writing to the memory controller in the cgroup filesystem, you’re instructing the kernel to enforce a memory ceiling for that specific process tree. It’s the difference between a well-behaved service and one that eventually triggers an OOM panic.

🚀 Pro-Tip: Check memory.failcnt inside that same cgroup directory to see if your service is constantly hitting that ceiling.

Linux Tips & Tricks | © ngelinux.com | 7/24/2026