Chapter 1 Introduction and Overview

The Sun Cluster product is an integrated hardware and software solution that you use to create highly available and scalable services. Sun Cluster Concepts Guide for Solaris OS provides the conceptual information that you need to gain a more complete picture of the Sun Cluster product. Use this book with the entire Sun Cluster documentation set to provide a complete view of the Sun Cluster software.

This chapter provides an overview of the general concepts that underlie the Sun Cluster product.

This chapter does the following:

• Provides an introduction and high-level overview of the Sun Cluster software

• Describes the several views of the Sun Cluster audience

• Identifies key concepts that you need to understand before you use the Sun Cluster software

• Maps key concepts to the Sun Cluster documentation that includes procedures and related information

• Maps cluster-related tasks to the documentation that contains procedures that you use to complete those tasks

This chapter contains the following sections:

• Introduction to the Sun Cluster Environment

• Three Views of the Sun Cluster Software

• Sun Cluster Software Tasks

Introduction to the Sun Cluster Environment

The Sun Cluster environment extends the Solaris Operating System into a cluster operating system. A cluster, or plex, is a collection of loosely coupled computing nodes that provides a single client view of network services or applications, including databases, web services, and file services.

Each cluster node is a standalone server that runs its own processes. These processes communicate with one another to form what looks like (to a network client) a single system that cooperatively provides applications, system resources, and data to users.

A cluster offers several advantages over traditional single-server systems. These advantages include support for failover and scalable services, capacity for modular growth, and low entry price compared to traditional hardware fault-tolerant systems.

The goals of the Sun Cluster software are:

• Reduce or eliminate system downtime because of software or hardware failure

• Ensure availability of data and applications to end users, regardless of the kind of failure that would normally take down a single-server system

• Increase application throughput by enabling services to scale to additional processors by adding nodes to the cluster

• Provide enhanced availability of the system by enabling you to perform maintenance without shutting down the entire cluster

For more information about fault tolerance and high availability, see Making Applications Highly Available With Sun Cluster in Sun Cluster Overview for Solaris OS.

Refer to High Availability FAQs for questions and answers on high availability.

Three Views of the Sun Cluster Software

This section describes three different views of the Sun Cluster software and the key concepts and documentation relevant to each view.

These views are typical for the following professionals:

• Hardware installation and service personnel

• System administrators

• Application developers

Hardware Installation and Service View

To hardware service professionals, the Sun Cluster software looks like a collection of off-the-shelf hardware that includes servers, networks, and storage. These components are all cabled together so that every component has a backup and no single point of failure exists.

Key Concepts – Hardware

Hardware service professionals need to understand the following cluster concepts.

• Cluster hardware configurations and cabling

• Installing and servicing (adding, removing, replacing):

  • Network interface components (adapters, junctions, cables)

  • Disk interface cards

  • Disk arrays

  • Disk drives

  • The administrative console and the console access device

• Setting up the administrative console and console access device

More Hardware Conceptual Information

The following sections contain material relevant to the preceding key concepts:

• Cluster Nodes

• Multihost Devices

• Local Disks

• Cluster Interconnect

• Public Network Interfaces

• Client Systems

• Administrative Console

• Console Access Devices

• SPARC: Clustered Pair Topology for SPARC

• SPARC: N+1 (Star) Topology for SPARC

Sun Cluster Documentation for Hardware Professionals

The Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS includes procedures and information that are associated with hardware service concepts.

System Administrator View

To the system administrator, the Sun Cluster software is a set of servers (nodes) that are cabled together, sharing storage devices.

The system administrator sees software that performs specific tasks:

• Specialized cluster software that is integrated with Solaris software to monitor the connectivity between cluster nodes

• Specialized software that monitors the health of user application programs that are running on the cluster nodes

• Volume management software that sets up and administers disks

• Specialized cluster software that enables all nodes to access all storage devices, even those that are not directly connected to disks

• Specialized cluster software that enables files to appear on every node as though they were locally attached to that node

Key Concepts –System Administration

System administrators need to understand the following concepts and processes:

• The interaction between the hardware and software components

• The general flow of how to install and configure the cluster including:

  • Installing the Solaris Operating System

  • Installing and configuring Sun Cluster software

  • Installing and configuring a volume manager

  • Installing and configuring application software to be cluster ready

  • Installing and configuring Sun Cluster data service software

• Cluster administrative procedures for adding, removing, replacing, and servicing cluster hardware and software components

• Configuration modifications to improve performance

More System Administrator Conceptual Information

The following sections contain material relevant to the preceding key concepts:

• Administrative Interfaces

• Cluster Time

• High-Availability Framework

• Global Devices

• Device Groups

• Global Namespace

• Cluster File Systems

• Disk Path Monitoring

• About Failure Fencing

• Data Services

Sun Cluster Documentation for System Administrators

The following Sun Cluster documents include procedures and information associated with the system administration concepts:

• Sun Cluster Software Installation Guide for Solaris OS

• Sun Cluster System Administration Guide for Solaris OS

• Sun Cluster Error Messages Guide for Solaris OS

• Sun Cluster 3.2 Release Notes for Solaris OS

• Sun Cluster 3.0-3.1 Release Notes Supplement

Application Developer View

The Sun Cluster software provides data services for such applications as Oracle, NFS, DNS, Sun Java System Web Server, Apache Web Server (on SPARC based systems), and Sun Java System Directory Server. Data services are created by configuring off-the-shelf applications to run under control of the Sun Cluster software. The Sun Cluster software provides configuration files and management methods that start, stop, and monitor the applications. If you need to create a new failover or scalable service, you can use the Sun Cluster Application Programming Interface (API) and the Data Service Enabling Technologies API (DSET API) to develop the necessary configuration files and management methods that enable its application to run as a data service on the cluster.

Key Concepts – Application Development

Application developers need to understand the following:

• The characteristics of their application to determine whether it can be made to run as a failover or scalable data service.

• The Sun Cluster API, DSET API, and the “generic” data service. Developers need to determine which tool is most suitable for them to use to write programs or scripts to configure their application for the cluster environment.

More Application Developer Conceptual Information

The following sections contain material relevant to the preceding key concepts:

• Data Services

• Resources, Resource Groups, and Resource Types

• Chapter 4, Frequently Asked Questions

Sun Cluster Documentation for Application Developers

The following Sun Cluster documents include procedures and information associated with the application developer concepts:

• Sun Cluster Data Services Developer’s Guide for Solaris OS

• Sun Cluster Data Services Planning and Administration Guide for Solaris OS

Sun Cluster Software Tasks

All Sun Cluster software tasks require some conceptual background. The following table provides a high-level view of the tasks and the documentation that describes task steps. The concepts sections in this book describe how the concepts map to these tasks.

Table 1–1 Task Map: Mapping User Tasks to Documentation

Task	Instructions
Install cluster hardware	Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS
Install Solaris software on the cluster	Sun Cluster Software Installation Guide for Solaris OS
SPARC: Install SunTM Management Center software	Sun Cluster Software Installation Guide for Solaris OS
Install and configure Sun Cluster software	Sun Cluster Software Installation Guide for Solaris OS
Install and configure volume management software	Sun Cluster Software Installation Guide for Solaris OS Your volume management documentation
Install and configure Sun Cluster data services	Sun Cluster Data Services Planning and Administration Guide for Solaris OS
Service cluster hardware	Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS
Administer Sun Cluster software	Sun Cluster System Administration Guide for Solaris OS
Administer volume management software	Sun Cluster System Administration Guide for Solaris OS and your volume management documentation
Administer application software	Your application documentation
Problem identification and suggested user actions	Sun Cluster Error Messages Guide for Solaris OS
Create a new data service	Sun Cluster Data Services Developer’s Guide for Solaris OS