Many domains require computer clusters to meet clients’ service level expectations. As cluster size increases, component failure becomes more likely. Rapid failure recovery is required to maintain high availability. The SA Forum has created specifications enabling management of multi-vendor solutions. These long-lived systems require tailored upgrade campaigns to keep their configuration up-to-date. Passed works on SA Forum’s Availability Management Framework (AMF) have created an automated AMF configuration generator and upgrade campaign generator. However, to generate an upgrade campaign for an already configured cluster based on a new target configuration, a configuration difference generator is needed. Furthermore, while Distinguished Names (DNs) usually uniquely identify object in a configuration, configuration generators do not guarantee that DNs in the new configuration will match. DN modification is not possible in a system without object replacement, causing service loss. Non-DN based inter-configuration object association is needed to restore old DNs. Our objective is to devise a technique to perform difference generation with limited knowledge of DNs and to find what data is needed to achieve this. To accomplish this, we analyse the AMF configuration model, then propose assumptions in a top down approach based on maintaining service availability during upgrade. We propose a two phase technique that first associates objects in-between configurations and then outputs the differences. We have implemented a tool that implements this technique on the Eclipse Platform and integrates with MAGIC’s Automated Upgrade Campaign Generator. We then present a case study based on the PHASE example.