How to stop an idle Service Fabric Cluster Upgrade?

Troubleshoot application upgrades says that -

"An UpgradePhase of PreUpgradeSafetyCheck means there were issues preparing the upgrade domain before it was performed.The most common issues in this case are service errors in the close or demotion from primary code paths."

So probably SF was not able to shut down service executable. The easiest way might be to Deactivate(restart) the node mentioned in the output from the SF Explorer.

What I did in the end was log onto the nodes in the cluster one by one and restart them, waiting for the previous one to come back up before restarting the next one.

This fixed it and the upgrade process eventually finished. The restart on the VMSS would probably have achieved the same thing, but I'm not sure whether there would have been a service outage during the restart. It certainly would have been less time consuming.

Two ways that I can see you accomplishing this:

• Kill the service fabric cluster and recreate it
• or preferably restart the Virtual Machine Scale Set (really the equivalent of restarting the servers). I'm sure there's a way to do this through Powershell instead of through the Azure portal.