Mastering Advanced Docker Run: Beyond Basic Container Execution

Most people learn Docker with one command: docker run ubuntu And then immediately hit confusion: Why did the container exit instantly? That single moment actually opens the door to understanding how Docker really works. This guide takes you beyond basic execution and into the practical flags every DevOps engineer should know for real container management. Why a Container Exits Immediately When you run: docker run ubuntu Docker pulls the image, starts a container, and exits almost immediately. Why? Because Docker containers live only as long as the main foreground process runs. Ubuntu itself does not start a continuous service by default, so the container stops right away. You can verify: docker ps -a You’ll see the container in exited state. Use Exact Image Versions Instead of latest A very common production mistake is relying on implicit latest tags. Example: docker run redis This means: docker run redis:latest That may silently change behavior later when upstream images update. Alway