Sometimes you need to run Docker containers in different circumstances, like on Raspberry Pi's or you have systems that are just wired differently (Alpine) and sometimes even a combination of those (Alpine on a BananaPi) and you do not always have everything laying around to reproduce it. So what do you do?

I ran into this problem because someone was getting a new Apple MacBook with the M1 chip which is ARMv8 or aarch64 and therefore all my previously made Docker images did not work anymore for this person as they did not work for his architecture.

Luckily Alpine and Debian also provide images for the ARMv8 architecture. Yet that meant I had to build two different images and have a multi arch manifest file inside AWS ECR. Which they support and is easy to do, but I did not want to have that plus it made it so difficult to try and reproduce things as I could build cross architecture but not run it yet.

Get yourself QEMU

So the following one line is all you need to make it possible to run as different architectures.

sudo docker run --rm --privileged multiarch/qemu-user-static:register

That will register all the necessary binaries in order to simulate the other architectures. Then for example run the following:

docker run -it --rm multiarch/alpine:aarch64-edge /bin/ash

Then you get an aarch64 image!.

Verify with uname -a and arch

Now you can see what it is like to run on those other architectures. The binaries are all of the form qemu-<ARCH>-static and so there is one for MIPS, SPARC and even PowerPC.

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