Container Basics On Linux (Namespaces/Cgroups)

See what a container is actually allowed to touch

🧩 The Challenge

Trying to figure out why your containerized app is hitting a wall with system resources feels like chasing ghosts. You end up digging through a mountain of documentation just to figure out why your memory limit is acting weird.

💡 The Fix

Peek directly into the proc filesystem to see what the kernel is enforcing on a specific process. It cuts through the abstraction layers that container runtimes love to pile on.

grep -E 'memory|cpu' /proc/$(pgrep -u appuser your_app_name)/cgroup

⚙️ Why It Works

By looking at the cgroup pseudo-files, you are seeing the raw enforcement state directly from the kernel instead of relying on whatever the container engine thinks is happening. That level of truth saves you from hours of guessing whether your limits are actually taking hold.

🚀 Pro-Tip: Pipe it into column -t if you are looking at multiple controllers at once so you don’t go cross-eyed reading the output.

Linux Tips & Tricks | © ngelinux.com | 10/15/2026