Learn how to deploy a Phoenix server on Raspberry Pi using k3s and Docker, from app creation to Kubernetes deployment. This guide provides detailed steps for setting up your environment and deploying your application.

Deploying a Phoenix Server on Raspberry Pi with k3s

In this guide, we’ll deploy a Phoenix server on a Raspberry Pi using K3s and Docker. This setup is similar to deploying a Node.js server.

Creating the Phoenix App

You can create the app inside the Docker container or on a different machine, but we’ll do it locally. First, install Erlang, Elixir, and Phoenix:

mix phx.new phoenix_server --no-ecto

If you answer ‘Y’ to the “Fetch and install dependencies?” prompt, it will take a while but save time during the Docker build step.


Create a Dockerfile with the following content:

# Use an official Elixir runtime as a parent image
FROM elixir:latest

# Install hex, rebar, and phoenix.
RUN mix local.hex --force \
    && mix local.rebar --force \
    && mix archive.install --force hex phx_new 1.4.12

# Install nvm
RUN curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.2/install.sh | bash

# Install node
RUN set -e \
    && NVM_DIR="$HOME/.nvm" \
    && . "$NVM_DIR/nvm.sh" \
    && nvm install $NODE_VERSION

# Create an app directory and copy the Elixir projects into it
RUN mkdir /app
COPY . /app

# Compile the project
RUN mix do deps.get, compile

RUN set -e \
    && NVM_DIR="$HOME/.nvm" \
    && . "$NVM_DIR/nvm.sh" \
    && cd assets \
    && npm install \
    && node node_modules/webpack/bin/webpack.js --mode development


CMD ["/app/docker-entrypoint.sh"]


Create a docker-entrypoint.sh script with the following content:


set -e

export NVM_DIR="$HOME/.nvm"
. "$NVM_DIR/nvm.sh"

cd /app
exec mix phx.server

Make it executable:

chmod +x docker-entrypoint.sh

Note that the above script runs the Phoenix app in development mode.

Creating the Docker Image

Build the Docker image using:

docker build -t phoenix-server .

Pushing to a Private Docker Repository

Tag and push the Docker image to your private repository:

docker tag phoenix-server rpi201:5000/phoenix-server
docker push rpi201:5000/phoenix-server

Creating a Deployment

Create a deployment in Kubernetes:

sudo kubectl create deployment phoenix-server --image=rpi201:5000/phoenix-server

Exposing the Deployment

Expose the deployment to make it accessible:

sudo kubectl expose deployment phoenix-server --port 4000

Checking the Deployment

Verify that the deployment is working:

sudo kubectl get endpoints phoenix-server

For more details, refer to the PSPDFKit blog post.

Following these steps, you can successfully deploy a Phoenix server on Raspberry Pi using k3s and Docker.