[FEATURE_REQUEST] Support ARMv7 Docker containers

[evroon]

When trying to run the docker container on a Raspberry Pi 4 with the default docker-compose.yml, the following is outputted in the logs:

standard_init_linux.go:228: exec user process caused: exec format error

This is most likely because the docker container is not built for ARM architectures.
So I now got Dashy working by building from source (after manually installing nodejs and yarn, because the Raspbian packages ship old versions).

Describe the solution you'd like
It would be nice to provide docker containers for ARM platforms.
I have never tried it, but I see that there is a runs_on option for Github Actions which you can use to run on ARM platforms.

Priority:
Low: Nice to have

[Lissy93]

Thanks for raising this, you're right that this issue is caused by ARM. I will work on this tomorrow, and get an ARM-compatible image released onto Docker Hub. Will update you on this issue once it's done :)

[Lissy93]

So with the below Dockerfile, replacing the base image from alpine:3.14 to arm32v7/alpine:3.14 should work, except DockerHub throws an error (I guess because it's building the container on amd64)

LinuxServer.io seems to support multiple architectures with manifested docker images using buildkit, but got no idea how they're building those images - the Docker docs on enabling BuildKit only covers local containers - I couldn't find a way to do this with DockerHub

I've seen other images using QEMU to emulate the build process on DockerHub, but again, haven't been able to find much info on how to actually do this. I'm thinking that maybe I need a GH action to build the image, and then publish it on DockerHub

@EVOTk or anyone, any ideas on how to approach this? I'm still a bit of a noob at Dockerizing apps, this was the first one I had done.

Dashy's Standard Dockerfile:

# Use stsnadard light-weight Alpine container as base
FROM alpine:3.14

# Install Node and Yarn
RUN apk add --update --no-cache nodejs npm yarn

# Define some Env Vars
ENV PORT 80
ENV DIRECTORY /app
ENV IS_DOCKER true

# Create and set the working directory
WORKDIR ${DIRECTORY}

# Copy over the 'package.json' and 'yarn.lock'
COPY package.json ./
COPY yarn.lock ./

# Install dependencies
RUN yarn

# Copy over all source code
COPY . .

# Build Dashy for production
RUN yarn build

# Expose the port
EXPOSE ${PORT}

# Finally, build the app and start the server
CMD [ "yarn", "build-and-start"]

# Run simple healthchecks every 5 mins, to check that everything's running smoothly
HEALTHCHECK --interval=5m --timeout=2s --start-period=30s CMD yarn health-check

Error caused by using `FROM arm32v7/alpine:3.14` on DockerHub

error: failed to solve: rpc error: code = Unknown desc = executor failed running [/bin/sh -c apk add --update --no-cache nodejs npm yarn]: exit code: 1
Build failed using Buildkit

[evroon]

Thank you for all the effort on trying to get this to work. Simply using the arm32v7 version of alpine as you mentioned seems to work on the Rpi 4 (it's a bit slow building the image of course ;) ).

I have experience with Docker but no experience with Docker Hub. There is an explanation here with a template Dockerfile on how to use QEMU to build ARM images on Docker Hub like you mentioned.

I will try myself to get it to work. If that works, I will create a PR.

[Lissy93]

Thanks again @evroon for providing the ARM-based Docker image
I'm super happy that it's finally working, and I hope it runs okay on your Pi :)

docker pull lissy93/dashy:arm64v8