Baragon

Baragon is a system for automating load balancer configuration updates. It pairs well with the Singularity Mesos framework.

Contents

• Baragon Basics
• Getting Started
  • Quick Start
  • Detailed Setup Guide
  • Example Baragon Service Configuration
  • Example Baragon Agent Configuration
• Quick Start With Docker Compose
• BaragonUI
• API Docs
• Developing

Baragon Basics

Baragon is made up of two services:

• BaragonService -- coordination service

• BaragonAgentService -- applies changes on the actual load balancer

When a web service changes (i.e. upstreams added / removed), POST a BaragonRequest JSON object to BaragonService's /[contextPath]/request endpoint like this one:

{
  "loadBalancerRequestId": "4",
  "loadBalancerService": {
    "serviceId": "1",
    "owners": ["foo"],
    "serviceBasePath": "/basepath",
    "loadBalancerGroups": ["loadBalancerGroupName"]
  },
  "addUpstreams": ["1.1.1.1:80"],
  "removeUpstreams": []
}

• BaragonService will fan out the update to all BaragonAgents in the specified loadBalancerGroups
• BaragonAgents will apply the changes on the load balancer using templates provided in its configuration and report back a Success or Failure to BaragonService
• Polling the BaragonService request status url (/[contextPath]/request/{loadBalancerRequestId}) will indicate the current status of the request

Check out the API Docs for additional BaragonRequest fields and returned values.

Getting Started

For more details on configuring and using Baragon, check out the detailed setup and management guide

** Prerequisite: A working ZooKeeper cluster **

1. Build JARs via mvn clean package.

2. Create a configuration file for Baragon Service and Baragon Agent. These are an extended version of a Dropwizard configuration file. Details on configurable fields can be found in the example configs below and in the detailed setup and management guide

• Example Baragon Service Configuration. This will be referenced as $SERVICE_CONFIG_YAML.
• Example Baragon Agent Configuration. This will be referenced as $AGENT_CONFIG_YAML.

3. Copy BaragonService-*-SNAPSHOT.jar and $SERVICE_CONFIG_YAML onto one or more hosts, and start the service via java -jar BaragonService-*-SNAPSHOT.jar server $SERVICE_CONFIG_YAML.

4. Copy BaragonAgentService-*-SNAPSHOT.jar and $AGENT_CONFIG_YAML onto each of your load balancer hosts. Start the BaragonAgent service via java -jar BaragonAgentService-*-SNAPSHOT.jar server $AGENT_CONFIG_YAML.

Quickstart with Docker Compose

To get an example cluster up and running, you can install docker and docker-compose.

Simply run docker-compose up to bring up:

• zookeper container
• Baragon Service container
• Two Baragon Agent + Nginx containers

The Baragon UI will be available at localhost:8080 and nginx at localhost:80.

If using boot2docker replace localhost with the boot2docker ip

Nginx's config directories that BaragonAgent writes to will also be mounted as volumes in the docker/configs folder on your local machine.

BaragonUI

Baragon comes with a UI for visualization and easier management of load balancer paths and upstreams. By default it will be available in a read-only mode at /[contextPath]/ui see the Example Baragon Service Configuration or detailed setup and management guide for more details on configuring BaragonUI behavior.

Baragon API Docs

Full documentation on the Baragon Service API can be found here