Front-end web servers

If you deploy an IBM® WebSphere® Application Server cluster within your IBM InfoSphere® Information Server implementation, you can provide a front-end web server upstream of the cluster.

InfoSphere Information Server supports IBM HTTP Server and Apache HTTP Server. These software products are not shipped with InfoSphere Information Server.

A front-end web server manages servlet and JSP requests. The web server typically uses an internal workload management (WLM) plug-in to dispatch web requests to the appropriate cluster members and their containers. It performs the dispatches according to policies that are preconfigured in the WLM plug-in. The front-end web server increases performance and security because the web server provides a unique HTTP entry point to the cluster.

To prevent single points of failure at the web server level, deploy a backup dedicated web server to take over in case the active one fails.

The following diagram shows an InfoSphere Information Server cluster with a front-end web server. A backup web server is also deployed.

Figure 1. Cluster with front-end web server
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If you choose IBM HTTP Server, you can set up the Deployment Manager to manage configuration and administration of the web server. The web server can be defined either as a managed node or an unmanaged node.
  • If you want to use the Deployment Manager to manage web servers in the same manner as any other managed nodes in the cell, define the web servers as managed nodes. For example, you can use the Deployment Manager to start or stop IBM HTTP Server or to install the IBM HTTP Server plug-in configuration file that contains the workload management policies that are defined for the cluster.
  • If you deploy the web servers upstream of a firewall that protects the cluster members, define the web servers as unmanaged nodes. In this case, you can manage the web servers with the Deployment Manager by enabling the IBM HTTP Server Admin Process on the same computer as the IBM HTTP Server by opening its port through the firewall.

The following diagram shows an IBM HTTP Server instance that is defined as a managed node. The Deployment Manager manages IBM HTTP Server through the local node agent.

Figure 2. IBM HTTP Server instance that is defined as a managed node
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The following diagram shows an IBM HTTP Server instance that is defined as an unmanaged node on a stand-alone server. A firewall separates the server from the cell. The Deployment Manager manages the IBM HTTP Server instance by using the IBM HTTP Server Admin Process.

Figure 3. IBM HTTP Server instance that is defined as an unmanaged node on a stand-alone server
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If you want to use the Apache HTTP Server outside of a firewall, you can run it as an unmanaged node. If you want the Apache HTTP server to be managed, then it must be on the same machine as a node agent that is managed by the deployment manager (as shown in Figure 2), and thus it cannot be on the other side of any firewall from the deployment manager. If unmanaged, copy the web server plug-in configuration files to each web server manually after services tier installation or a fix pack installation.

Figure 4. Apache HTTP Server
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Parent topic: A front-end configuration to an IBM WebSphere Application Server cluster