Introduction
In this article we will explore how to use QEMU to run emulating the ARM32v7 architecture to build and run Rust code like if it was a native ARM32v7 architecture.
There are some drawbacks and performance considerations when using this approach, it can be simpler but way slower for big projects.
The source for this article is here RCV and the docker image is here.
This article can be considered a part 2 of Running rust on ARM32v7K3S Oracle cluster so we will not be creating the rust project and all that here, but focusing on building and running the project.
Prerequisites
Let’s jump to the example
The new Dockerfile
You will notice that this Dockerfile
is way simpler than the ones from the previous article, since it runs natively
as ARM32v7, the main difference is the base image being arm32v7/rust:1.63.0, this can be further extended for more
architectures, see this article for
more information.
Last steps for QEMU/Docker
After installing the required packages you will still need to perform some simple steps in order for it to work with docker and buildah, the first command is needed for docker to be able to use the required QEMU emulation and the second is just to validate that everything works fine
Short names error
If you get an error about short names when pulling images add the following line to your /etc/containers/registries.conf
file
Lets build it
For the build we will use buildah because it is smarter than docker for this kind of scenarios.
Lets test it
After building it, we can push it to the docker daemon and then run it and test it from another terminal
Notice: you will see some warnings about the architecture, that’s fine as we are emulating things.
Performance considerations
This project build with the rust toolchain and then copied to an ARM32v7 image took 2 minutes, but using QEMU and the given emulation it took around 8 minutes and a half, so it is something to be aware since the difference is quite big.
Extra
You can see it running here, a very basic HTML Curriculum vitae.
For more details and to see how everything fits together I encourage you to clone the repo, test it, and modify it to make your own.
Closing notes
Be sure to check the links if you want to learn more about the examples, I hope you enjoyed it, see you on twitter or github!
The source for this article is here
Errata
If you spot any error or have any suggestion, please send me a message so it gets fixed.
Also, you can check the source code and changes in the generated code and the sources here