rpi-nano-httpd

A nano sized web server packed into a Docker Nano Container

Step 1: Compile the assembly source code

Compiling the ASM source to a statically linked ARM binary for Raspberry Pi.

The source can be found in src/ folder. You need a x86/amd64 Linux machine to compile the source assembly code with FASM (can be downloaded from http://arm.flatassembler.net). You only need the statically compiled fasmarm binary. I've done it within a Ubuntu 14.04 (64bit) machine running as a Docker Container.

Compile the thing just with ./fasmarm httpd.fasm httpd

cd ./src/
docker run --rm -ti -v $(pwd):/src ubuntu:14.04 bash -c 'cd /src && ./fasmarm httpd.fasm httpd'
flat assembler for ARM  version 1.71.39  (16384 kilobytes memory)
3 passes, 4328 bytes.

Now we've got a super small httpd binary with 4kByte only

ls -al httpd
-rwxr-xr-x  1 dieter  staff  4328 Jun 28 16:27 httpd

And hell yeah, it's statically linked

file httpd
httpd: ELF 32-bit LSB executable, ARM, version 1 (SYSV), statically linked, stripped

Let's copying it to ./docker/ folder

cp httpd ../docker/

Step 2: Create the Docker Nano Image

cd ./docker/
make

Now we do have a ready-to-run Docker Image with a single statically linked ARM binary for use on a Raspberry Pi.

docker images
REPOSITORY               TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
hypriot/rpi-nano-httpd   0.1.0               0fd6d79d7479        15 minutes ago      87.7 kB
hypriot/rpi-nano-httpd   latest              0fd6d79d7479        15 minutes ago      87.7 kB

Please note, the size of the Docker Image includes the payload too! Without the payload the image size would be 4kByte only! Ok, that's not nano anymore, that's more pico sized.

Step 3: Now let's run a lot of these containers on our Raspberry Pi

To start 10 web servers use the following command

./start-webservers.sh 10

To ramp up to 100 web servers use the following command

./start-webservers.sh 100 10

That's it, have fun.

Acknoledgements

httpd, original source code

https://www.raspberrypi.org/forums/viewtopic.php?p=320919

I was so happy to find this small piece of source code after hours. It's a minimal web server or httpd written in assembly language to run on an ARM cpu. I did only a minor change and use index.html as the default resource to look for. As the source code is written for FASM you also need to download this tool too.

FASMARM: Freeware ARM cross assembler for FASM

http://arm.flatassembler.net

Just download the package for a Linux distro and extract the tool fasmarm which is a statically linked binary and doesn't need any additional dependencies installed.