Container Resource Limits

Memory Limits

Set hard memory limits to prevent a container from consuming all host memory:

# Limit to 512MB RAM
docker run -d --memory=512m my-app

# Memory + swap limit
docker run -d --memory=512m --memory-swap=1g my-app

# Disable swap entirely
docker run -d --memory=512m --memory-swap=512m my-app

OOM Killer Behavior

When a container exceeds its memory limit, the Linux OOM killer terminates it. Control this with:

# Disable OOM killer (container hangs instead of being killed)
docker run -d --memory=512m --oom-kill-disable my-app

# Adjust OOM priority (-1000 to 1000, lower = less likely to be killed)
docker run -d --memory=512m --oom-score-adj=-500 my-app

CPU Limits

# Limit to 1.5 CPUs
docker run -d --cpus=1.5 my-app

# CPU shares (relative weight, default 1024)
docker run -d --cpu-shares=512 my-app

# Pin to specific CPU cores
docker run -d --cpuset-cpus="0,1" my-app

Monitoring Resource Usage

# Real-time stats
docker stats my-app

# Single snapshot
docker stats --no-stream --format "table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}" my-app

# Check limits via inspect
docker inspect --format '{{.HostConfig.Memory}}' my-app

In Docker Compose

services:
  api:
    image: my-api
    deploy:
      resources:
        limits:
          cpus: '2.0'
          memory: 1G
        reservations:
          cpus: '0.5'
          memory: 256M