How to fix Error response from daemon: Container is not running in Docker

First, list all containers including stopped ones to identify your container:

docker ps -a

Look for the STATUS column. If it shows "Exited (0)", the process completed normally. A non-zero exit code indicates an error. Note the container ID or name.

Check the logs to understand why the container stopped:

docker logs <container_id>

Look for error messages, stack traces, or application crashes that caused the exit. This often reveals missing environment variables, connection failures, or startup errors.

If the container simply needs to be restarted:

docker start <container_id>

Then verify it's running:

docker ps | grep <container_id>

If it starts successfully, you can now run exec commands or access logs.

If the container exits immediately, run it interactively to debug:

docker run -it <image_name> /bin/bash

Or override the entrypoint to get a shell:

docker run -it --entrypoint /bin/sh <image_name>

This allows you to explore the container environment and test commands manually.

Docker containers need a foreground process to stay running. If your CMD or ENTRYPOINT exits, the container stops. Common fixes:

Bad (exits immediately):

CMD echo "Hello"

Good (runs indefinitely):

CMD ["nginx", "-g", "daemon off;"]
# or
CMD ["node", "server.js"]
# or for debugging
CMD ["tail", "-f", "/dev/null"]

Ensure your Dockerfile's CMD or ENTRYPOINT starts a long-running process.

To automatically restart containers after host reboots or crashes:

docker run -d --restart unless-stopped <image_name>

Or update an existing container:

docker update --restart unless-stopped <container_id>

Restart policies: no (default), on-failure, always, unless-stopped.