Docker Images for arm64 releases (Raspberry Pi)

[shalzz]

Description

Hello,
Please also consider providing Docker Image releases for arm64/aarch64 platforms along with amd64 Docker Images on Docker Hub.

[paulhauner]

Good idea. Seems like dockerhub doesn't support it natively but we can do it via Github Actions: https://www.henry.wang/2019/12/05/arm-dockerhub.html

I don't have bandwidth for this at the moment, but I think it's worth doing.

[paulhauner]

Marked as low-hanging-fruit since it's a relatively simple way to make a material difference to users.

[paulhauner]

@realbigsean this might interest you :)

[realbigsean]

A few notes on making a multi-arch image:

• it's not doable using Dockerhub atm, but it is in their roadmap. I also tried using a workaround using emulation, but their build servers are too old.
• it's doable using github actions and QEMU, but takes a looooong time (~5 hours). I also went down the rabbit hole of trying to use cross-compilation to speed things up, but cross uses docker, so you end up needing to start a docker container within a docker build which gets hairy. (I think cross also uses QEMU so I don't know whether it'll speed stuff up)
• I think the solution that's the most straightforward and likely to result in the fastest builds is to run a docker builder node on an ARM64 and one on an AMD64 server and coordinate them

[michaelsproul]

cross uses docker, so you end up needing to start a docker container within a docker build which gets hairy. (I think cross also uses QEMU so I don't know whether it'll speed stuff up)

Building an ARM binary with cross doesn't use QEMU, and is quite fast. I think we could do something like:

1. Build ARM binary using cross, on "bare metal" (no nested Docker, but probably under a hypervisor)
2. Copy that binary into a base image as we currently do in the 2nd stage of our build:

lighthouse/Dockerfile

Lines 9 to 16 in c6baa0e

	FROM debian:buster-slim
	RUN apt-get update && apt-get install -y --no-install-recommends \
	libssl-dev \
	ca-certificates \
	&& apt-get clean \
	&& rm -rf /var/lib/apt/lists/*
	COPY --from=builder /usr/local/cargo/bin/lighthouse /usr/local/bin/lighthouse
	COPY --from=builder /usr/local/cargo/bin/lcli /usr/local/bin/lcli

[realbigsean]

@michaelsproul I got something working in #2065 using cross first like you suggested and then docker buildx to cross-build the docker image, and then docker manifest to make the multi-arch image. Let me know your thoughts

It's way faster 🔥