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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
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