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:
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Provides an introduction and high-level overview of the Sun Cluster software
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Describes the several views of the Sun Cluster audience
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Identifies key concepts that you need to understand before you use the Sun Cluster software
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Maps key concepts to the Sun Cluster documentation that includes procedures and related information
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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
The Sun Cluster environment extends the Solaris Operating System into a cluster operating system. A cluster is a collection of one or more nodes that belong exclusively to that collection. In a cluster that runs on the Solaris 10 OS, a global cluster and a zone cluster are types of clusters.
In a cluster that runs on any version of the Solaris OS that was released before the Solaris 10 OS, a node is a physical machine that contributes to cluster membership and is not a quorum device. In a cluster that runs on the Solaris 10 OS, the concept of a node changes. In this environment, a node is a Solaris zone that is associated with a cluster. In this environment, a Solaris host, or simply host, is one of the following hardware or software configurations that runs the Solaris OS and its own processes:
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A “bare metal” physical machine that is not configured with a virtual machine or as a hardware domain
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A Sun Logical Domains (LDoms) guest domain
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A Sun Logical Domains (LDoms) I/O domain
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A hardware domain
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.
In a Solaris 10 environment, a global cluster is a type of cluster that is composed only of one or more global-cluster voting nodes and optionally, zero or more global-cluster non-voting nodes.
Note –
A global cluster can optionally also include solaris8, solaris9, lx (Linux), or native brand, non-global zones that are not nodes, but high availability containers (as resources).
A global-cluster voting node is a native brand, global zone in a global cluster that contributes votes to the total number of quorum votes, that is, membership votes in the cluster. This total determines whether the cluster has sufficient votes to continue operating. A global-cluster non-voting node is a native brand, non-global zone in a global cluster that does not contribute votes to the total number of quorum votes, that is, membership votes in the cluster.
In a Solaris 10 environment, a zone cluster is a type of cluster that is composed only of one or more cluster brand, voting nodes. A zone cluster depends on, and therefore requires, a global cluster. A global cluster does not contain a zone cluster. You cannot configure a zone cluster without a global cluster. A zone cluster has, at most, one zone cluster node on a machine.
Note –
A zone-cluster node continues to operate only as long as the global-cluster voting node on the same machine continues to operate. If a global-cluster voting node on a machine fails, all zone-cluster nodes on that machine fail as well.
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:
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Reduce or eliminate system downtime because of software or hardware failure
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Ensure availability of data and applications to end users, regardless of the kind of failure that would normally take down a single-server system
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Increase application throughput by enabling services to scale to additional processors by adding nodes to the cluster
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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:
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Hardware installation and service personnel
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System administrators
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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.
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Cluster hardware configurations and cabling
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Installing and servicing (adding, removing, replacing):
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Network interface components (adapters, junctions, cables)
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Disk interface cards
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Disk arrays
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Disk drives
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The administrative console and the console access device
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Setting up the administrative console and console access device
More Hardware Conceptual Information
The following sections contain material relevant to the preceding key concepts:
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 product is a set of Solaris hosts that share storage devices.
The system administrator sees software that performs specific tasks:
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Specialized cluster software that is integrated with Solaris software to monitor the connectivity between Solaris hosts in the cluster
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Specialized software that monitors the health of user application programs that are running on the cluster nodes
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Volume management software that sets up and administers disks
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Specialized cluster software that enables all Solaris hosts to access all storage devices, even those Solaris hosts that are not directly connected to disks
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Specialized cluster software that enables files to appear on every Solaris host as though they were locally attached to that Solaris host
Key Concepts – System Administration
System administrators need to understand the following concepts and processes:
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The interaction between the hardware and software components
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The general flow of how to install and configure the cluster including:
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Installing the Solaris Operating System
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Installing and configuring Sun Cluster software
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Installing and configuring a volume manager
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Installing and configuring application software to be cluster ready
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Installing and configuring Sun Cluster data service software
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Cluster administrative procedures for adding, removing, replacing, and servicing cluster hardware and software components
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Configuration modifications to improve performance
More System Administrator Conceptual Information
The following sections contain material relevant to the preceding key concepts:
Sun Cluster Documentation for System Administrators
The following Sun Cluster documents include procedures and information associated with the system administration concepts:
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:
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The characteristics of their application to determine whether it can be made to run as a failover or scalable data service.
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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:
Sun Cluster Documentation for Application Developers
The following Sun Cluster documents include procedures and information associated with the application developer concepts:
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 |
|---|---|
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Install cluster hardware |
Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS |
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Install Solaris software on the cluster | |
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SPARC: Install SunTM Management Center software | |
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Install and configure Sun Cluster software | |
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Install and configure volume management software |
Sun Cluster Software Installation Guide for Solaris OS Your volume management documentation |
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Install and configure Sun Cluster data services |
Sun Cluster Data Services Planning and Administration Guide for Solaris OS |
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Service cluster hardware |
Sun Cluster 3.1 - 3.2 Hardware Administration Manual for Solaris OS |
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Administer Sun Cluster software | |
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Administer volume management software |
Sun Cluster System Administration Guide for Solaris OS and your volume management documentation |
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Administer application software |
Your application documentation |
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Problem identification and suggested user actions | |
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Create a new data service |
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