coreos-consul-haproxy

Run your own cloud cluster: CoreOS+Fleet+Consul+Haproxy

Architecture

CoreOS provides native support to etcd, fleet and docker. This project adds a layer for easy service discovery, registry and reaching. This is done using Consul for service registry, registrator for discory and haproxy for reaching the services.

Cloud-config explained

If you don't understand the content of the cloud-config file, you can find more information in the projet's wiki page cloud-config explained.

Deploy your service

In order to deploy your services, a blank.service is provided. You can customize it however you like. It contains commented out section for Fleet to show you what you can do with it.

Two unit service

If you have a meta-service that has a web-server and a database, the best practice is to have the web-server act as a "sidekick" to the database.

For example, the database is simply declared as website_db.service:

[Unit]
Description=Database for the website
Requires=docker.service
After=docker.service
RequiresMountsFor=/data

The website (website_www.service) however depends upon the database:

[Unit]
Description=Website
Requires=docker.service
After=docker.service website_db.service
PartOf=website_db.service
RequiresMountsFor=/data

...

[X-Fleet]
MachineOf=website_db.service

In this setting the website will follow the database wherever it goes in the cluster.

cloud-config-server support

The ejs/ folder contains the template file for the cloud-config-server. The entrypoint is the file cfch.ejs.

Usage

Launch cloud-config-server:

docker run --rm -it --name cloud -v $PWD/ejs:/data:ro -p 8080:8080 auguster/cloud-config-server

Then query the cloud-config file:

http://localhost:8080/cfch

Parameters

List of available parameters

• host sets the hostname of the instance (default to host)
• domain sets the domain of the instance, used for etcd DNS discovery (default to empty)
• dataserver sets the NFS server's address (data[.domain])
• timezone sets the timezone for the instance (default to Europe/Paris)
• consul sets the URL of a consul server (default to domain). Overwritten by bootstrap.
• bootstrap puts the instance in bootstrap mode. Choose the number of expected cluster member for bootstrap. Etcd might be broken while in bootstrap mode (not fully tested).