What is Caddy?
From the website
Caddy is an alternative web server that is easy to configure and use.
and
A web server that serves you Other web servers were designed for the Web, but Caddy was designed for humans, with today’s Web in mind.
This wonderful piece of software is a perfect fit for my 6-Node Cluster of Raspberries!
Here is an example:
Caddy is super easy to install and to configure. See this video how to setup caddy running HTTPS and get automatically a valid certificate from Let’s encrypt.
Back to my idea
But back to the basics and see how to create a docker service. I want to run caddy as a docker service. To install docker, please see my Quickstart-Installation guide.
What is a Docker service?
Frequently a service will be the image for a microservice within the context of some larger application.
What?!
To deploy an application image when Docker Engine is in swarm mode, you create a service.
Ok, docker needs to run in swarm mode… see the Quickstart Docker Swarm
Lets get started
We need a docker image
Based on abiosoft/caddy-docker I’ve created a dockerfile for the Raspberry Pi which can be found on GitHub and Dockerhub
Create a docker service
$ docker service create --name caddy-service --publish 2015:2015 --replicas 6 pixelchrome/caddy-arm
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Check
$ docker service ls
ID NAME MODE REPLICAS IMAGE
m4xs9p90h2jj caddy-service replicated 1/6 pixelchrome/caddy-arm:latest
$ docker service ps caddy-service
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
ej0njtn4dkl0 caddy-service.1 pixelchrome/caddy-arm:latest pi3 Running Running 2 minutes ago
n33ikkyy9ygr caddy-service.2 pixelchrome/caddy-arm:latest pi6 Running Running about a minute ago
h0rwye2zbk2j caddy-service.3 pixelchrome/caddy-arm:latest pi5 Running Running about a minute ago
k4wal0jegcag caddy-service.4 pixelchrome/caddy-arm:latest pi2 Running Running 2 minutes ago
ie91uryxhxwq caddy-service.5 pixelchrome/caddy-arm:latest pi1 Running Running 2 minutes ago
s8bas4humy84 caddy-service.6 pixelchrome/caddy-arm:latest pi4 Running Running about a minute ago
On each Raspberry Pi is one instance of caddy running!
Remove the service
$ docker service rm caddy-service
caddy-service
$ docker service ls
ID NAME MODE REPLICAS IMAGE
Customize
If you need more specific settings you can change the Caddyfile or you want to host more than just the default index.html file, please find some examples below. These files or directory have to be available on each node of the swarm!
Mount a specific “Document Root” (e.g. /var/www of the Raspian)
$ docker service create --name caddy-service --publish 2015:2015 --replicas 6 --mount type=bind,source=/var/www,target=/srv pixelchrome/caddy-arm
A specific Caddyfile
$ docker service create --name caddy-service --publish 2015:2015 --replicas 6 --mount type=bind,source=<PATH>/Caddyfile,target=/etc/Caddyfile pixelchrome/caddy-arm
A combination of both examples from above
$ docker service create --name caddy-service --publish 2015:2015 --replicas 6 --mount type=bind,source=/home/pi/example/Caddyfile,target=/etc/Caddyfile --mount type=bind,source=/var/www,target=/srv pixelchrome/caddy-arm
Next article
Caddy runs now independently on each node of the swarm. It is time to put a load balancer in front of it. Stay tuned…