docker pull ubuntu

docker run ubuntu

docker ps -a

CONTAINER ID   IMAGE     COMMAND       STATUS                     PORTS   NAMES
123abc456def   ubuntu    "/bin/bash"   Exited (0) 3 seconds ago   ---     bold_blackburn

f you’ve ever tried running an Ubuntu container on macOS (or any system) and noticed that it stops immediately, you’re not alone.

You might see something like this in Docker Desktop:

✅ Docker is running (green icon)

🧱 Image is downloaded

❌ Container won’t stay alive

Let’s break down why that happens — and how to fix it like a pro 💪

---

🧩 The Problem

You pull the image:

docker pull ubuntu

Then try to run it:

docker run ubuntu

But when you check:

docker ps -a

You see:

CONTAINER ID   IMAGE     COMMAND       STATUS                     PORTS   NAMES
123abc456def   ubuntu    "/bin/bash"   Exited (0) 3 seconds ago   ---     bold_blackburn

👉 It starts and exits immediately! You might wonder: “Why is my container not staying alive?”

💡 The Reason

A Docker container only runs as long as its main process is running.

When you start the ubuntu image, it runs /bin/bash by default. But if you don’t attach to it interactively, that shell exits right away.

Think of it like opening a terminal window that instantly closes because you didn’t type anything.

⚙️ The Fix — Run It Interactively

Start the container with an interactive shell:

docker run -it ubuntu

You’ll now drop into a shell like:

root@b7f9c4f8f9e0:/#

🎉 Boom! The container stays alive because you’re inside it.

You can explore, install packages, and do anything:

apt update && apt install curl

When you type exit, it will stop again — as expected.

🏷️ Add a Name to Manage It Easily

Add a friendly name to your container:

docker run -it --name myubuntu ubuntu

Now you can easily restart or attach later:

docker start -ai myubuntu

No need to remember a random container ID!

🌀 Keep It Running in the Background

If you want your Ubuntu container to stay alive in the background, you need a process that never ends. For example:

docker run -d --name myubuntu ubuntu tail -f /dev/null

Here’s what’s happening:

-d →detached mode (runs in background)

tail -f /dev/null →keeps the process alive forever

Now check:

docker ps

You’ll see your container happily running 😄

🔍 Summary

Mode	Command	Behavior
Basic	docker run ubuntu	Starts and exits immediately
Interactive	docker run -it ubuntu	Opens shell, stays alive
Named	docker run -it --name myubuntu ubuntu	Easier to manage
Background	docker run -d --name myubuntu ubuntu tail -f /dev/null	Persistent background container

💬 Final Thoughts

So, the reason your Ubuntu container wasn’t running wasn’t a Docker Desktop bug — it was just Docker doing exactly what it should. Containers are designed to run a single process, not act as full-blown virtual machines (though you can make them behave like one 😉).

If you remember this golden rule 👇

🧠 “No running process → container exits.”

…you’ll never be confused again.