Oracle Enterprise Manager 12c is a systems management framework consisting of an Oracle database, Oracle WebLogic, a J2EE application, an application development frame work 11g (ADF) administrative Web GUI, server and client side plug-ins, and a client side agent. In the context of Oracle Enterprise Manager, the Oracle database repository is named the “Oracle Management Repository” or “OMR”. WebLogic is the J2EE platform called the “Oracle Management Service” or “OMS”, that runs the Oracle Enterprise Manager 12c J2EE application. The administrative Web GUI is named Oracle Enterprise Manager Cloud Control. The client side agents are named the “Oracle Management Agents” or “OMA”. The server and client side plug-ins share a unique name for the managed product or technology. Monitored hosts are referred to as targets. All of the Oracle Enterprise Manager components are commonly referred to as Oracle Enterprise Manager (OEM) or Enterprise Manager (EM).
The Oracle Management Repository, the Oracle Management Service along with the Oracle Management Agent can be installed on a single x86-64 Linux host in an all-in-one configuration or in an n-tier configuration. Traditionally, production Oracle Enterprise Manager environments are not be placed on a single server, nor should the Oracle Management Repository be shared with production or test databases on the same server. For production, the Oracle Management Repository as well as WebLogic should be on dedicated virtual or physical servers. If your Oracle Enterprise Manager environment starts out small, make sure to have a plan to scale out your Oracle Enterprise Manager infrastructure.
Each of the Oracle Enterprise Manager 12c components can be installed using the Oracle Universal Installer (OUI) GUI, or using silent installation scripts, or with the software only, configure later installation mode. The software only installation mode allows you to install only the Oracle Enterprise Manager software binaries without any configurations. The software only installation mode is ideal if you want to install the software at one point and configure the software later.
There are several Oracle Enterprise Manager 12c design options that can employed depending on the size and critically of your Enterprise Manager enviroment. For example, for evaluations an all-in-one Oracle Enterprise Manager 12c design could be deployed with the Oracle Management Repository and the Oracle Management Service installed on a single Linux node. For small and medium sites a multiple node Oracle Enterprise Manager 12c design could be deployed with the Oracle Management Repository installed on one Linux node, and the Oracle Management Service installed on a second Linux node. If your site's target count requires two Oracle Management Services or Databases, you'll need to deploy a high availability design with two Oracle Management Services with a load balancer, and/or a second Database with RAC for the Oracle Management Repository.
Figure 1 shows a high availability Oracle Enterprise Manager 12c design with the Oracle Management Service on two Linux nodes with a load balancer, a third Linux node with the Oracle Management Repository, servicing various targets. High availability Oracle Enterprise Manager 12c designs are ideal for medium and large sites.