Setting Up Web Application on NAS

Steps to Deploy:

1️⃣ Login to the NAS

2️⃣ Build the Docker Container

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.

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

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`.

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

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

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
```