Docker Container Stops Automatically After docker run -d — Why and How to Fix It

Running containers in detached mode using:

docker run -d <image>

is a common practice. But sometimes, the container stops immediately after starting. This can be confusing, especially if you expect it to stay running.

Let’s understand why this happens and how to fix it.

Table of Contents

1️⃣ Why Does It Stop?

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

When you run docker run -d <image>, Docker:

Starts a container
Executes the command specified in the Dockerfile (CMD or ENTRYPOINT)
Stops the container as soon as that command finishes

If the command is short-lived (e.g., echo "Hello"), the container will exit right away.

Example:

docker run -d alpine echo "Hello"

This prints “Hello” and exits — so the container stops immediately.

2️⃣ Common Causes

No long-running process — Image was built for a single task, not a service.
Wrong command — You overwrote the default command with something that finishes quickly.
Misconfigured entrypoint — Script runs and exits without keeping the container alive.

3️⃣ How to Diagnose

Check container logs: docker logs <container_id>
Inspect container exit status: docker ps -a If the container is stopped, note the STATUS or Exit Code.

4️⃣ How to Keep a Container Running

Option 1 — Run a Long-Running Service

If you want the container to host something like Nginx:

docker run -d nginx

This stays running because nginx is a service that doesn’t exit immediately.

Option 2 — Override Command to Keep Alive

Use a process like tail -f or sleep:

docker run -d alpine tail -f /dev/null

This keeps the container running without doing anything.

Option 3 — Interactive Mode

For debugging, use:

docker run -it <image> sh

You’ll be inside the container until you exit.

Option 4 — Check Your Dockerfile

If building your own image:

CMD ["your", "long-running", "command"]

Ensure your container runs something that keeps running, like a server.

📌 Summary

Rule: A Docker container stops when its main process exits.
Fix: Run a long-running command or keep the process alive.
Use docker logs and docker ps -a to see why it stopped.