Using Android Device as a Linux Server

It is possible to use Android device as a Linux server. With a few tools and apps, you can run web servers, SSH, and more — all from your Andoird. You can even make it publicly accessible over the internet.

Prerequist

Android device
Cloudflare account with domain
Some Linux skill

First of all you need to install Termux which is a terminal emulator and Linux command-line environment. You can install Termux from here. We will run all commands inside Termux from here on.

Upgrade Termux Packages

pkg update
pkg upgrade

Install Apache Web Server

For this example, we will setup an apache web server. Start by installing it:

pkg install apache2

Run Apache Web Server

apachectl

To check if the server is running visit http://localhost:8080 from your Android device.

Now your Android device is running a web server. You can also run a Node.js app by installing Node.js.

Next, we’ll make the server publicly accessible using Cloudflare Tunnel.

Note: You must have a domain already added to your Cloudflare account to use Cloudflare Tunnel.

Install Cloudflare Tunnel Client

pkg install cloudflared

Login to Cloudflare

cloudflared tunnel login

It will open a browser for login. After logging in, select a hostname (domain) to grant access. It will create an account certificate file (cert.pem) in the default cloudflared directory (~/.cloudflared).

Create a Tunnel

cloudflared tunnel create my-tunnel

my-tunnel is your tunnel name, which you will need later. It will also create a tunnel credentials file ({UUID}.json).

Create a Config

Create a config.yml file inside ~/.cloudflared directory with following content. Replace the {UUID} with the id generated while creating the tunnel. And <domain> with the hostname you gave access while login.

tunnel: {UUID}
credentials-file: /data/data/com.termux/files/home/.cloudflared/{UUID}.json
ingress:
  - hostname: tunnel.<domain>
    service: http://localhost:8080
  - service: http_status:404

http://localhost:8080 is the localhost server URL running in the Android device. cloudflared will respond with a 404 status code when the request does not match any of the previous hostnames.

Start Routing Traffic

cloudflared tunnel route dns my-tunnel tunnel.<domain>

It will assign a CNAME record that points traffic to your tunnel subdomain.

Run the Tunnel

cloudflared tunnel run my-tunnel

Now you can access https://tunnel.<domain> from any network.

The official documentation covers everything you may need to know about creating tunnels and configuring it. You can refer to it for more advanced setup and troubleshooting.