Upgrade of cluster install does not upgrade build number in shared home confluence.cfg.xml

Since Confluence 6.1, Data Center has stored a copy of the confluence.cfg.xml in the shared home directory, to simplify booting new cluster nodes in AWS and Azure deployments. Upgrading a Data Center install since this release does not trigger upgrades of this xml file, which can lead to new nodes having an old build number in their local home directory (since they copy the file from shared home as part of their initial setup process). This in turn can lead to fast-failing upgrades later, due to the 3-way validation check on the build number in the local home directory, and the database, and the code being deployed.

Confluence must update the xml file in the shared home after any upgrade tasks are executed - ideally by the node that executes database upgrade tasks.

Workaround

After completing an upgrade on a single node, the system administrator can manually copy the confluence.cfg.xml from a properly upgraded local home into the shared home. This will ensure that further fresh nodes will have an upgraded configuration.