Setting Up Web Application on NAS

• Date:* 05/08/2025

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1️⃣ Login to the NAS

• Use SSH to access the NAS:

                        ssh username@nas_ip
                      
                    

2️⃣ Build the Docker Container

• Navigate to the app's directory on the NAS:

                    cd /path/to/your/app
                  
                

• Build the Docker image:

                  docker build -t myapp-image .
                
              

3️⃣ Start the Docker Container

• Run the container and expose the necessary ports:

              docker run -d --name myapp-container -p 8080:8080 myapp-image
            
          

4️⃣ Expose the Port in the Docker Network

• Verify that the port 8080 is mapped and accessible inside the NAS:

          docker port myapp-container
        
      

• Check connectivity from NAS to the Docker container:

        curl http://localhost:8080
      
    

5️⃣ Configure the Web Server Application on the NAS In Web Portal Settings, select configure new settings

• Open the Web Server App interface on your NAS.

• Add a Reverse Proxy or Port Forwarding entry:

  • Source Port: 8080
  • Destination IP: localhost or the Docker container IP
  • Destination Port: 8080

• Ensure the web server points correctly to the Docker container.

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• Login to NAS: ssh username@nas_ip
• Build Docker Image: docker build -t myapp-image .
• Run Docker Container: docker run -d --name myapp-container -p 8080:8080 myapp-image
• Check Docker Ports: docker port myapp-container
• Test Port Access: curl http://localhost:8080

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• Dockerfile configured properly
• Port mapped correctly in Docker
• NAS Web Server App proxy configured
• Test connection from NAS web server to container

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Problem	Possible Cause	Solution
Cannot access the app from the NAS	Port mapping issue or firewall restriction	Check Docker port mapping: docker port myapp-container and NAS firewall settings.
curl http://localhost:8080 fails	Container not running or wrong port	Run docker ps to check the container status. Make sure it exposes 8080.
Web server not reaching the container	Incorrect IP or reverse proxy settings	Use Docker IP with docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' myapp-container.
Docker container exits unexpectedly	Crash inside the app or bad Dockerfile	Run docker logs myapp-container to view error messages.
Port already in use	Conflict with another service	Find the process with sudo lsof -i :8080 and kill if necessary.
Changes not visible after redeploy	Old image still running	Stop and remove old container: docker rm -f myapp-container, then restart.
Network bridge issues	Docker network misconfiguration	Restart Docker networking: sudo systemctl restart docker.

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Command	Description
docker ps	List all running containers
docker ps -a	List all containers (running and stopped)
docker images	List all Docker images
docker logs	View logs for a specific container
docker stop	Stop a running container
docker start	Start a stopped container
docker restart	Restart a running container
docker rm	Remove a stopped container
docker rmi	Remove a Docker image
docker exec -it bash	Access the container's shell for debugging
docker inspect	View detailed information about a container
docker network ls	List all Docker networks
docker network inspect	Inspect a Docker network
docker system prune	Remove all stopped containers, unused networks, and dangling images
docker volume ls	List all Docker volumes
docker volume prune	Remove unused Docker volumes

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• If you want to access the container from another device, use the NAS IP address and the exposed port:

            http://nas_ip:8080
          
        

• Ensure your NAS firewall allows the port (e.g., 8080).

• To link containers during docker run:

            docker run --name container1 --link container2:alias_name -d myapp-image
          
        

• Inside container1, you can access container2 by the hostname alias_name.

• Create a Docker network:

            docker network create myapp-network
          
        

• Run containers on the same network:

          docker run --network myapp-network --name backend -d backend-image
          docker run --network myapp-network --name frontend -d frontend-image
        
      

• Containers can communicate using container names:

        curl http://backend:8080
      
    

• Bridge Mode (default): Isolated networking, port mappings required.

• Host Mode: Directly uses the host's network stack. Run with:

            docker run --network host -d myapp-image