An open source high availability middleware solution

based on the Application Interface Specification from

the Service Availability Forum™

What is OpenSAF?

OpenSAF is an open source community with projects

focused on high availability middleware. The goal of

OpenSAF projects is to develop HA middleware that is

consistent with the Service Availability™ Forum (SA

Forum™) specifications. OpenSAF software is freely

available to anyone under the LGPL v2.1 license, and

anyone may contribute to the code base.

The SA Forum has authored specifications in two key areas

of core middleware. The first, the Application Interface

Specification, delivers services for creating highly available

applications and services. The second SA Forum

specification is the Hardware Platform Interface, which is

focused on managing hardware. OpenSAF includes an open

source implementation of the SA Forum’s AIS specification.

OpenSAF software is designed to be the core component of

a highly available software stack that can be used in

mission-critical applications in many industries, including

telecommunications, military and aerospace, financial and

industrial automation. The OpenSAF software, combined

with a carrier grade class of operating system and fault-

tolerant hardware, can be used to build network elements

and other equipment, such as mission critical defense

systems, meeting stringent system availability requirements.

OpenSAF is designed to be flexible and adaptable enough to

work on many different kinds of hardware platforms and

operating systems. It is a highly scalable and modular

architecture that can be used in many types of devices,

ranging from small access points to large packet switches.

By standardizing on OpenSAF across multiple product lines,

organizations can take advantage of a standards-based,

Commercial-Off-The-Shelf (COTS) open source middleware

component to deliver more cost-effective solutions for

complex networks such as next-generation broadband or 4G

LTE networks.

The latest release of the OpenSAF high availability (HA)

middleware project, OpenSAF 4.0, became available in

July 2010. Go to the OpenSAF Foundation website at

www.opensaf.org for more information, or download

OpenSAF at: http://devel.opensaf.org/wiki/downloads.

In addition to the OpenSAF software, a full set of

documentation describes all the services. A set of sample

applications and makefiles is included that eases the

development of applications. The sample applications

illustrate the use of the various APIs and serve as a starting

point for development.

OpenSAF 4.0 introduces several key new features that

improve scalability, hardware and software management.

The OpenSAF code base was re-architected to be much

more modular. The effect of this is improved scalability and

packaging for applications that do not require all the services

available with OpenSAF. Other key services include the

Software Management Framework, which allows

management of both OpenSAF, as well as application code.

This provides in-place upgrade capabilities for applications.

The Platform Management S ervice provides a bridge

between OpenSAF and the Hardware Platform Interface

specification.

OpenSAF Release 4.0

Highly Available Applications

Other Middleware and Application Services(Database, Java, Protocols)

Linux Operating Systemwith HA or Other Carrier Grade Features

Redundant Hardware Platforms

SA Forum HA Middleware Services

HW Management(HPI Middleware)

OpenSAF(AIS Middleware)(AIS Middleware)

OpenSAF(AIS Middleware)

OpenSAF

Figure 1. Components of a highly available system

using OpenSAF

Benefits of Using OpenSAF 4.0

As industries continue to migrate from proprietary software

to solutions based on open source, there is an increasing

demand for an open source-based middleware solution that

meets high availability industry standard interface

specifications. Because OpenSAF is an open source

solution, there are additional benefits not found with

proprietary implementations:

• Leverage of a broad community of developers

• Open Source business models and licensing

• Fast innovation of the open source model

• Modular architecture that allows companies to use only the

services they need while providing a future-proof solution

for next-generation devices

• A complete ecosystem, including commercial OpenSAF

providers, hardware vendors supporting OpenSAF and

ISVs that are integrating support for OpenSAF/AIS services

in their applications

• Flexibility of having multiple suppliers offering the same

core, standards-based implementation

SA Forum Services

The following table lists the Application Interface

Specification (AIS) services implemented in OpenSAF

Release 4.0.

AIS Service SA Forum

Specification

Availability Management Framework (AMF) B.01.01

Checkpoint Service (CKPT) B.02.02

Cluster Membership Service (CLM) B.04.01

Event Service (EVT) B.03.01

Global Lock Service (LCK) B.01.01

Information Model Management Service (IMM) A.02.01

Log Service (LOG) A.02.01

Message Service (MSG) B.03.01

Notification Service (NTF) A.01.01

Platform Management Service (PLM) A.01.02

Software Management Framework (SMF) A.01.01

Message Distribution Service (MDS over TIPC)

SA Forum Information Management Model

SA Forum-based AIS Services Additional Services

Syst

em D

escr

iptio

n XM

L

SA Forum Cluster Membership

Message-based Checkpoint Service

Distributed Tracing Service

Persistent Store Service

HPI Integration Service

SA Forum Message Service

SA Forum Log Service

SA Forum Lock Service

SA Forum Platform Management Service

SA Forum SW Management Framework

SA Forum Notification Service

SA Forum Event Service

SA Forum Checkpoint Service

SA Forum Availability Management Framework

Figure 2. OpenSAF 4.0 architecture

The AIS services are implemented in OpenSAF Release 4.0

as follows:

Availability Management Framework – Provides a

standardized means to model system components and

standardized mechanisms for monitoring, fault reporting,

fault recovery and repair of components. The OpenSAF 4.0

AMF implementation supports the AMF B.04.01 information

model and implementation is conformant to AMF B.01.01.

Checkpoint Service – Coordinates the creation and

deletion of checkpoints and maintains the checkpoint

inventory within a cluster.

Cluster Membership Service – Defines which computing

elements are in the cluster and allows them to join or leave

membership. This defines the key scope of operation for the

availability framework and the other SA Forum-based

services. In this release, CLM is re-architected and upgraded

to the latest CLM B.04.01 conformance.

Event Service – Provides a standardized means to publish

events and to subscribe to events anywhere in a cluster.

Global Lock Service – Provides a means to control access

to cluster resources by competing distributed clients.

Information Model Management Service – Provides a

mechanism for AIS services and applications to configure

and manage using the SA Forum AIS information model. In

OpenSAF 4.0 all the AIS services are integrated with the

information model defined by the SA Forum for the

respective services.

Log Service – Collects high-level function-based information

for use by network or system administrators or automated

tools to assist in troubleshooting misconfigurations, lost

network connections and related operational issues.

Message Service – Provides a standardized means for

distributed applications to send messages among

themselves.

Notification Service – Enables applications to be updated

on the state of the system and enables the availability

service to take appropriate action based on the indications it

receives.

Platform Management Service – New in Release 4.0, this

service matches the configured system to the hardware

actually present and makes hardware states easily

accessible for software via the information model. PLM also

extends the IMM with objects that represent operating

systems and virtualization layers.

Software Management Framework – New in Release 4.0,

the Software Management Framework (SMF) enables

system developers to create capabilities to manage various

software components within the system.

Additional OpenSAF Services

OpenSAF includes a set of additional services that are

necessary for an implementation of high availability

middleware. These services address additional requirements

for a complete service availability solution.

Distributed Trace Service – Allows clients to direct debug

information to a file for later analysis.

Message-Based Checkpointing Service – Provides

message-based checkpointing between an active

component and one or more stand-by components. It is

especially useful when large amounts of active call “state”

information must be passed between redundant entities.

Message Distribution Service – Provides a reliable

message distribution mechanism, working on top of TIPC.

HPI Integration Service – Creates a consistent interface for

other OpenSAF services to access HPI events and to invoke

HPI functions.

Persistent Store Service – Uses the standard Linux DRDB

service that provides a lightweight mechanism for storing

state information. The stored, persistent information may be

used by a component when it is restarted.

For More Information

To learn more about OpenSAF Release 4.0 or the OpenSAF

project, visit the website at http://www.opensaf.org/, which is

maintained by the OpenSAF Foundation. The OpenSAF

Foundation is a not-for-profit organization established by

leading communications and computing companies to

facilitate the work of the OpenSAF project and to accelerate

the adoption of OpenSAF in commercial products.

OpenSAF AIS Services

OpenSAF Foundation

401 Edgewater Place

Suite 600

Wakefield, MA 01880 USA

Phone +1 781 876-8998

Fax +1 781 623-0480

www.opensaf.org