Docker interview questions!

📌 How would you troubleshoot a Docker container that is stuck in an “Exited” state immediately after starting?

✅ First, check the logs of the container using docker logs <container_id>. The logs often provide clues about what went wrong.

✅ Check the exit code of the container using docker inspect <container_id> or docker ps -a.

✅ An exit code of 137 typically means the container was killed due to memory limits.

✅ Exit code 1 often means an application error, while 143 is typically a result of the container receiving a SIGTERM.

✅ If there are no obvious application errors, inspect the Dockerfile for issues with the ENTRYPOINT or CMD instructions. If these are incorrectly set or missing, the container will exit immediately.

✅ Verify if the host has enough system resources, such as CPU, memory, or disk space. You can check this with docker stats or docker system df.

📌 You observe that a container is consuming an excessive amount of memory. How do you troubleshoot this?

✅ Use the docker stats command to check the live memory usage of containers.

✅ If the memory consumption is high, you might consider:

✅ Adding memory limits using – memory or – memory-swap flags when starting the container to restrict its memory usage.

✅ Check if there are memory leaks in the application by reviewing the application logs or…