Components of ArcGIS for Server

GIS resources such as maps and globes that have been made available on ArcGIS for Server are referred to as services. The purpose of an ArcGIS Server site is to receive requests to the services, fulfill them, and send results back to client applications that need to use them. The GIS server provides a set of tools that allow you to manage the services; for example, you can use the ArcGIS Server Manager application to add and remove services.

It's useful to understand how an ArcGIS Server site is put together so that you can build a site where GIS services run efficiently and fulfill the needs of your applications. This topic serves as an introduction to the components of an ArcGIS Server site.

The following components constitute an ArcGIS Server site:

• GIS server—The GIS server does the work of fulfilling requests to your web services. It draws maps, runs tools, queries data, and performs any other action you can do with a service. The GIS server can consist of one machine or many machines working together. The machines all have access to the same data and configuration information, so you can easily grow or shrink the number of participating machines in response to demand.

  The GIS server exposes your services through the common web protocol HTTP. When you install the GIS server, you immediately have a set of web services you can use in your apps. You can supplement the GIS server with an enterprise web server for more functionality, such as the ability to host web apps.

  GIS servers can be organized in groups, called clusters. Each cluster runs a dedicated subset of services, as configured by the server administrator. For example, you could create one cluster to run all your map services and another cluster of servers (perhaps with higher processing power) to run your geoprocessing services.

• Web Adaptor—To integrate your GIS servers with your existing enterprise web server, you can install the ArcGIS Web Adaptor. The Web Adaptor receives web service requests through a common URL (on a port and site name you choose) and sends them to the various GIS server machines in your site.

  You can alternatively expose your site through other types of "web gateway" technologies, such as an HTTP load balancer, network router, or third-party load balancing software. In some cases, it may be appropriate to use the Web Adaptor in tandem with your existing load balancing solution.

• Web server—A web server can host web applications and provide optional security and load balancing benefits to your ArcGIS Server site. If you just need basic hosting of GIS services, you can use the site that you create after installing ArcGIS Server.

  If you need to go beyond simple hosting of services, or if you want to use your organization's existing web server, you can install the Web Adaptor. The Web Adaptor allows you to integrate your ArcGIS Server site with IIS, WebSphere, WebLogic, and other web servers.

• Data server—You can place your data directly on each GIS server, or access it from a central data repository, such as a shared network folder or an ArcSDE geodatabase. Whichever option you choose, the data includes all the GIS resources that have been published as services on the GIS server. These resources can be maps, globes, locators, geodatabases, and so on.

To read about the above components in greater detail, see the topic Inside an ArcGIS Server site.

The people component

The software components described above are of no use without people to author the data, maintain the services, and use the services. An expanded view of the ArcGIS Server site includes content authors, server administrators, application developers, and end users of applications that use the GIS services.

• ArcGIS Server site administrators—An ArcGIS Server site needs someone to install the software, configure web applications, and tune the site for the best performance. ArcGIS Server site administrators can use ArcGIS for Desktop or ArcGIS Server Manager to administer the site. Administrators may enlist the help of developers or learn scripting skills themselves in order to automate administrative tasks through the ArcGIS Server Administrator API.
• ArcGIS for Desktop content authors and publishers—The GIS resources that will be published to the site, such as maps, globes, and geodatabases, are created by ArcGIS for Desktop content authors using applications such as ArcMap, ArcCatalog, and ArcGlobe. These applications can also help with the process of publishing the resources to the server.
• Application developers—Application developers take the services from an ArcGIS Server site and make them easily available to web, mobile, and desktop users through focused applications. You don't need advanced programming skills to consider yourself a developer. It's possible to use preconfigured viewers, templates, widgets, and samples to create web applications that look appealing and perform most common map navigation and query functions. More experienced developers have a broad range of API choices, including the power of ArcObjects available through server object extensions.
• Client application users—Web, mobile, and desktop applications can connect to services. The end users of these applications depend on the ArcGIS Server site for GIS data and analysis; however, they may not know details about the site or what services are available. A thorough knowledge of the number of end users accessing an ArcGIS Server site, as well as their usage patterns, can be valuable to you when planning the size and scope of your deployment.
• Others—Many other people may use or directly influence the ArcGIS Server site. These include IT administrators who coordinate the setup and architecture of the site, GIS managers who set requirements for the site, and GIS technicians who create the data. Although these individuals may not use the site every day, they may need to be trained on some of the ArcGIS Server site fundamentals and the best practices included in this help system.