The CIM Repository Synchronization for Cloud Computing is a tool to synchronize Common Information Model (CIM) repoitories which are deployed on different servers. The tool can be used in an Ensemble or a cloud environment, and can be used to easily update CIM schema or data in repositories among multiple servers.

CIM is an industry-standard way to describe data about applications and devices. It allows administrators and software management programs to control applications and devices on different platforms in the same way, ensuring interoperability across a network such as the Internet. The CIM model specification for these devices is presently under development through the Distributed Management Task Force (DMTF).

The CIM Object Manager (CIMOM) allows CIM object management on a Web-Based Enterprise Management (WBEM)-enabled system. A CIM object is a representation, or model, of a managed resource such as a printer, a disk drive, or a CPU. In order for hardware devices to be managed using CIM, a management console application must communicate with a CIMOM server.

CIM is composed of a specification and a schema. The specification defines the details for integration with other management models, and the schema provides the actual model descriptions. These schemas are written by the DMTF in a language called Managed Object Format (MOF). The schema works well for CIM providers implemented for OpenPegasus, an open-source implementation of the DMTF CIM and WBEM standards. This implemented module is called a CIM Object Manager (CIMOM). It is designed to be portable and highly modular, and runs today on most versions of UNIX, Linux, OpenVMS, and Microsoft Windows.

How does it work?

The CIM Repository Synchronization for Cloud Computing tool introduces a new method to synchronize the schema to multiple cimservers on a management domain. The method uses the SLP service to discover all active CIM servers on the management domain. You can select one of nodes which has the latest version schema, then make other nodes synchronize the repository with central node. The repository upgrade action is done by standard CIM operation like createClass or modifyClass. So, the method can help you upgrade all the CIM agents on the management domain parallel.

There are several benefits to this method:

1. Schema upgrading is done in parallel by standard CIM operation. System administrator can easily synchronize all the CIM servers on different systems. Compared with the traditional method, it is more effectively and efficiently.
2. CIM Server does not have to stop during the schema upgrade, which make the CIM server keeping service.
3. Only the standard CIM classes will be upgraded, the logic will not touch those customer's own objects.

The method also provides an option to have an "exclude" list for those classes you don't want to upgrade. The class in the exclude list will not be synchronized.

Liu Jun Feng is an advisory software engineer at IBM China Systems & Technology Laboratory, where he focuses on system management software design and development.

Jin Xin Ying, a software engineer, has been working on the CIM for IBM i and virtualization management at IBM Systems and Technology's Beijing development lab since January 2006. He focuses on CIM provider development.