Microsoft Knowledge Base Article 895092 contains the following INTRODUCTION:
This article describes the hotfixes and the updates that we recommend that you install on each node of a Microsoft Windows Server 2003-based server cluster. When you update your Windows Server 2003-based server cluster, you help reduce downtime. You also help decrease the number of support issues that you may experience.
Note We recommend that you evaluate these hotfixes and updates to determine whether they resolve problems in your environment. If you determine that cluster nodes that are in your environment may be affected by the problems that an update or a hotfix addresses, install the hotfix or the update on each one of the cluster nodes that are in your environment.
A short summary is included with each hotfix and update that appears in the "More Information" section. This summary does not replace the information that is contained in the original Microsoft Knowledge Base (KB) article for that particular hotfix or update. Use this summary information to help you determine whether a particular hotfix or update applies to your server cluster. Before you install a particular hotfix or update, we recommend that you review the original KB article that describes that hotfix or update.