Run Docker on an Android phone: install a headless Alpine Linux QEMU virtual machine in Termux

infoivonblog.nkfjt@aleeas.com (Ivon Huang) — Sun, 19 Dec 2021 14:00:00 +0800

Note: if you only want to run Docker, the method described in this article does not perform well. For a more practical approach, see this article: Run Docker On Android

We need to go deeper…

Basically, Android phones cannot run docker directly, because the kernel simply does not support it. Even so, we still have QEMU virtual machines, though unfortunately KVM is not usable either.

Architecture: create a QEMU virtual machine in the Termux emulator, install Docker inside the virtual machine, and then forward ports.

Phone: Sony Xperia 5 II, Android 11, 8GB RAM.

Take a simple Apache server as an example, and see whether the phone’s browser can display a web page created by docker inside the virtual machine. The web page content is as follows:

1. Create the virtual machine & install Docker
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Open Termux and enter the command:

pkg install qemu-utils qemu-common qemu-system-x86_64-headless

Download the Alpine Linux operating system ISO that includes virt

mkdir alpine && cd $_
wget http://dl-cdn.alpinelinux.org/alpine/v3.12/releases/x86_64/alpine-virt-3.12.3-x86_64.iso

Create a 4GB virtual hard disk

qemu-img create -f qcow2 alpine.img 4G

Boot

qemu-system-x86_64 -machine q35 -m 1024 -smp cpus=2 -cpu qemu64 \
 -drive if=pflash,format=raw,read-only,file=$PREFIX/share/qemu/edk2-x86_64-code.fd \
 -netdev user,id=n1,hostfwd=tcp::2222-:22 -device virtio-net,netdev=n1 \
 -cdrom alpine-virt-3.12.3-x86_64.iso \
 -nographic alpine.img

setup-interfaces
#Available interfaces are: eth0.
#Enter '?' for help on bridges, bonding and vlans.
#Which one do you want to initialize? (or '?' or 'done') [eth0]
#Ip address for eth0? (or 'dhcp', 'none', '?') [dhcp]
#Do you want to do any manual network configuration? [no]
ifup eth0

Use the answerfile prepared by oofnikj to install the system quickly.

wget https://gist.githubusercontent.com/oofnikj/e79aef095cd08756f7f26ed244355d62/raw/answerfile

Let it output messages during boot

sed -i -E 's/(local kernel_opts)=.*/\1="console=ttyS0"/' /sbin/setup-disk

Install the system to the hard disk. During this process, it will ask you to create a password for the root account.

setup-alpine -f answerfile

First use the poweroff command to shut down, then use this command to start the virtual machine (you can save it as a script yourself):

qemu-system-x86_64 -machine q35 -m 2048 -smp cpus=2 -cpu qemu64 \
 -drive if=pflash,format=raw,read-only=on,file=$PREFIX/share/qemu/edk2-x86_64-code.fd \
 -netdev user,id=n1,hostfwd=tcp::2222-:22,hostfwd=tcp::8081-:80 -device virtio-net,netdev=n1 \
 -nographic alpine.img
# m allocates 2GB memory, cpu is a 2-core CPU, and hostfwd forwards the phone's port 8081 to the virtual machine's port 80.

Install docker, and configure the virtual machine to start the service automatically on boot.

apk update && apk add docker
service docker start
rc-update add docker

2. Install the Apache server
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Pull the Apache server image

docker pull httpd

Run the Apache container, forward the virtual machine’s port 80 to the Docker container’s port 80, and map the docker container’s file path to the system’s /root/website directory.

docker run -d -p 80:80 --name myapache -v /root/website/:/usr/local/apache2/htdocs/ httpd

Create a test web page

mkdir website && cd website
vi index.html

Put this into the web page:

<!DOCTYPE html>
<html>
<body>
<h1>My Apache Server</h1>
<img src="https://c.tenor.com/61yCyJVoyr8AAAAd/%E6%A1%B6%E7%A5%9E-%E6%89%93%E5%B7%A5.gif">
</body>
</html>

Open the browser on the phone and enter localhost:8081/index.html; the Docker web page appears successfully.

3. Summary
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Running Apache Server with a virtual machine + Docker seems fine, but if you run something like a Minecraft server, the performance loss becomes very obvious.

Alpine Linux on Ivon's Blog

Run Docker on an Android phone: install a headless Alpine Linux QEMU virtual machine in Termux

1. Create the virtual machine & install Docker #

2. Install the Apache server #

3. Summary #

1. Create the virtual machine & install Docker
#

2. Install the Apache server
#

3. Summary
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