Making changes to Gosu code in a rolling upgrade

It is generally safe to add new Gosu classes to Guidewire PolicyCenter during a rolling upgrade. However, as Gosu is prevalent throughout PolicyCenter, modifications to Gosu code during a rolling upgrade can affect nearly every part of the behavior of PolicyCenter. Thus, Guidewire explicitly recommends that you do not modify existing Gosu classes during a rolling upgrade.

By definition, a rolling upgrade means that some nodes in a multi-node system pick up changes from the upgrade before other nodes. Thus, changes in Gosu code can cause some nodes to behave differently than other nodes while the rolling upgrade is in progress. For a full upgrade, this is not an issue, because you must shut down every node in the cluster before you start the upgrade. However, for a rolling upgrade, the lack of a consistent behavior is a major concern.

Do not modify, change, or delete Gosu code during a rolling upgrade of a PolicyCenter cluster.