After I have been using a total overkill setup for my private hosting a k3s cluster, for more than two years, I decided to cut some costs and complexity. I have now switched to a Kamal Deploy setup which is based on Docker. This takes care of SSL certificates from Let's Encrypt and deploying containers with zero downtime.

In sort in a Docker based deployment, with a proxy in front that takes care of routing and SSL certificates.

Prerequisite

• Linux Server with ssh access, I prefer Debian based Linux Distributions.

Setup

To use Kamal you first need to installed it. It's writing in Ruby so you would need to have that installed.

gem install kamal

After installing it, you run

kamal init

which will generate a boilerplate config/deploy.yml and a .kamal-directory which is used for secrets and hooks. I have not done any adjustments to the .kamal-directory.

As it's a boilerplate file config/deploy.yml, there are a lot of section commented out, my config/deploy.yml now looks like this.

# Name of your application. Used to uniquely configure containers.
service: dk-tomasnorre-blog
# Name of the container image.
image: tomasnorre/blog

# Deploy to these servers.
servers:
  web:
    - 116.203.152.185

# Enable SSL auto certification via Let's Encrypt and allow for multiple apps on a single web server.
proxy:
  ssl: true
  host: blog.tomasnorre.dk

# Credentials for your image host.
registry:
  # Specify the registry server, if you're not using Docker Hub
  server: docker.tomasnorre.dk
  username: registry

  # Always use an access token rather than real password (pulled from .kamal/secrets).
  password:
    - KAMAL_REGISTRY_PASSWORD

# Configure builder setup.
builder:
  arch: amd64

As it's all based on docker you would need a Dockerfile too, mine look like this

FROM composer:2 AS builder
WORKDIR /app
COPY . .

RUN composer install --no-dev --optimize-autoloader \
    && ./vendor/bin/jigsaw build production

FROM nginx:alpine
COPY config/nginx-default.conf /etc/nginx/conf.d/default.conf
COPY --from=builder /app/build_production/. /usr/share/nginx/html
COPY source/assets/robots.txt /usr/share/nginx/html/robots.txt
RUN echo `TZ='Europe/Copenhagen' date` > /usr/share/nginx/html/last_build.txt

An important part of Kamal is the /up-health check endpoint. You can set up Nginx simply by adding following to your nginx configuration in the server {} section.

    # Health check endpoint for Kamal
    location = /up {
        return 200 'OK';
        add_header Content-Type text/plain;
    }

As you can see it's fairly simple, it's a matter of building the static HTML and serving them with Nginx.

Deployment

After this is done, you can now deploy it with a simple command.

kamal deploy

Extra

What I have not covered here is the option to used databases like MySQL, Redis and other services together with Kamal. This can be done with accessories, which will configure the addtional needed containers for you.