How to fix Container exited with status code 1 in Docker

The first step is to examine what the application logged before exiting. Use docker logs to view stdout and stderr:

docker ps -a
docker logs <container-id>

Look for error messages, stack traces, or warnings that indicate what failed. Common patterns include "No such file or directory", "Permission denied", "ModuleNotFoundError", or database connection errors.

Ensure that your Dockerfile's CMD and ENTRYPOINT directives point to files that actually exist in the container:

# Check that these paths are correct
CMD ["/app/start.sh"]
ENTRYPOINT ["python", "app.py"]

You can inspect the container filesystem to verify:

docker run --rm -it <image> /bin/sh
ls -la /app/

If using a shell script as your entrypoint, ensure it's executable and has a proper shebang line:

# In Dockerfile, make script executable
COPY start.sh /app/start.sh
RUN chmod +x /app/start.sh

Ensure your script starts with:

#!/bin/bash
# or
#!/bin/sh

Note: Line endings matter. If you edited the script on Windows, convert CRLF to LF:

dos2unix start.sh

Check that all runtime dependencies are present in the container. For Python:

COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

For Node.js:

COPY package*.json .
RUN npm ci --only=production

Use multi-stage builds to keep the final image clean while ensuring all build dependencies are available during compilation.

Run your application outside of Docker to isolate whether the issue is container-specific:

# For Python
python app.py

# For Node.js
node server.js

If it works locally but fails in Docker, the issue is likely related to:
- Missing files not copied into the image
- Different environment variables
- Path differences (/app vs relative paths)
- Missing system packages

Ensure all required environment variables are set and accessible:

# Pass environment variables at runtime
docker run -e DATABASE_URL=postgres://... <image>

# Or use an env file
docker run --env-file .env <image>

In docker-compose.yml:

services:
  app:
    environment:
      - DATABASE_URL=${DATABASE_URL}
      - API_KEY=${API_KEY}
    # or
    env_file:
      - .env

Add debug logging to verify environment variables are loaded correctly.

Sometimes container state becomes corrupted. Stop, remove, and recreate the container:

# Stop and remove container
docker stop <container-id>
docker rm <container-id>

# Remove the image and rebuild
docker rmi <image>
docker build -t <image> .
docker run <image>

For docker-compose:

docker-compose down
docker-compose up --build