Atlas LBaaS overview

Atlas LBaaS Overview

September 2012

Atlas Architecture tenets

• Database is the source of truth – Configuration on devices is enforced to match DB

• LBaaS APIs that change state are asynchronous – Operations return as soon as DB is updated

– Devices are updated in the background

• Scaling in Atlas is achieved through – Use of async operations through ActiveMQ

– Use of Cluster of Atlas servers

Atlas Server scalable and HA deployment

Atlas infrastructure dependency

• Atlas infrastructure is based on: – Any Java Server (Jetty, Tomcat, Glassfish, JBOSS, etc.)

– Spring framework (IoC, annotations, xml config)

– JAXB (for generating API objects and mapping to REST)

– Dozer (utility to map between Java classes)

– Abstraction of persistence providers (JPA) => DB, ORM and Transactions

– Abstraction of message queueing (JMS) => Message Queues

– Unit testing framework (SureFire)

Tenant API specification

• Multi-Tenant API • Specification: wiki.openstack.org/Atlas-LB • Follows OpenStack API design recommendations • Determined after careful research into the common

capabilities of open source and commercial load balancers. • Specified using XML Schema file (XSD)

– API POJO classes generated from spec.

• Supports both JSON and XML – JSON payload generated from XML schema – ATOM support skeleton is there

• Can list active extensions • Support account limits

Atlas Plugins and extensions

Core

Extension

A D A P T E R

Core API

Extension API

Atlas Core

Core Resource Model

REST Layer

Persistence Service Layer

(transactions)

Persistence Repository

Layer (ORM)

MQ Consumers

Device Adapter

REST Layer

JAXB (XSD files)

Atlas data-model component

XML request JSON request JAX-RS (CXF)

Resource classes

JAXB object

Atlas API component

Dozer Mapper

1 2 3

4 5

Service classes

Atlas persistence component

Repository Classes

(Hibernate)

Async classes

7

DB

6 8

Atlas API component

Atlas API component

Message Queue (ActiveMQ)

Entity Object

JAXB object

Entity Object

Entity Object

9 Response

Message Queue (ActiveMQ)

Async classes

(Listeners)

Consume message

Atlas persistence component

Repository Classes

(Hibernate)

DB

ID

ReverseProxy Service

Adapter classes

Endpoint config Entity

Object

Entity Object

Entity Object

Network

LB Device LB Device

LB Device LB Device

LB Device

Endpoint config

Reads

1

2 3

4

5

6

7 Device-specific

API 8 Update

status

Atlas adapter component

Adapters

Adapter Tasks

• Minimum sharing with Core – Only what is specified in the interface

• Translates Atlas APIs and semantics to device API or configuration

• Manages IPv4 and IPv6 address pools • Manages devices. Could include onboarding and failure

detection • Manages rollback on failure to ensure device config

stays correct • Decides on device placement for each load balancer • Reports back any errors to core

Core Adapter Contract

Adapter Core Usage interface

Extensions

Rackspace Extended Adapter

Citrix Extended Adapter

Validation Framework

Notification Service

Scheduled Jobs

Atlas Extension Structure

• Extend the core XSD to specify new APIs or extension into existing APIs

• Extend the resource layer

• Extend the Service Layer

• Extend the Repository layer

• Extend the Async layer

• Extend the adapter layer

Example of extending API

packaging

• Java WAR file

• Debian package

• Adapters are built as separate JAR files

• Extensions are built as separate JAR files

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