Windows Cluster Development-write Microsoft Cluster Server (MSC) Resource DLL: 3) Microsoft Cluster Server Architecture

Microsoft Cluster Server Architecture

Consisting of three key parts:

• Cluster Service

• Resource Monitoring

• Resource and cluster management extension DLL

Cluster Service

The cluster service (composed of event processor, failover Manager/Resource Manager, Global Update manager, and other components) is the core component of MSC and runs as a high-priority system service. The cluster service controls cluster activities and provides tasks such as Collaborative Event Notifications, inter-cluster communication, failover, and configuration management. Each cluster node runs its own cluster service.

Resource Monitor

Resource Monitor is an interface between cluster services and cluster resources and runs as an independent process. The cluster service uses Resource Monitor to communicate with resource DLL. The resource monitor processes all the communications with the resource, thus blocking improper operations or functions out of the cluster service. Multiple copies of the Resource Monitor can be run on a single node, which provides a way to isolate unpredictable resources from other resources.

Resource DLL

Resource DLL is the third key component of MSC. Resource Monitor and resource DLL use resource API to communicate. Resource API is a collection of entry points, callback functions, related structures, and macros used for resource management. If an application implements its own resource DLL to communicate with the cluster service and uses the cluster API to request and update cluster information, it can be called a cluster-aware application. Applications and service programs that do not use the cluster or resource API and cluster control functions cannot perceive the cluster or know whether the MSC is running. Programs that are not perceptible to these clusters are generally managed by common applications or service programs.

Applications that are perceptible or imperceptible to the cluster can run on the cluster node and be managed as cluster resources. However, only clusters can perceive the benefits of cluster servers through cluster APIs. For example, the cluster can perceive the application:

• The status is reported based on the requirements of the Resource Monitor.

• Elegantly responds to online or offline requests.

• More precise responseIsaliveAndLooksaliveRequest.

The MSC contains two tools for basic cluster management: the Cluster Manager (cluadmin.exe)and the command line management tool (cluster.exe ). You are encouraged to develop custom management tools based on your own needs. However, further discussions on managing unperceptible applications in clusters or developing cluster management tools are beyond the scope of this article.

Figure 2 shows how the cluster service, resource manager, and resource DLL interact with each other on a single node running Windows NT Server, Enterprise Edition operating system, and cluster management application, including cluster awareness and cluster awareness applications.

Figure 2. msc component running on a single node on Windows NT Server

Note that the cluster-Aware Application should also implement the cluster management extension DLL, which contains the implementation of interfaces from the cluster management extension API. The cluster management extension DLL allows applications to be configured in the cluster management tool (cluadmin. EXE. Custom resources and Cluster Management Extensions DLL allow special management of corresponding and related resources, and make system management tools more convenient to install and configure applications.

The next section describes the details of resource and resource DLL, and describes the reasons for compiling Custom Resource DLL.