We recently needed to add the Microsoft.Powershell.DSC extension to our VMSS that contain our service fabric cluster. We redeployed the cluster using our ARM template, with the addition of the new extension for DSC. During the deployment we observed that as many as 4 out of 5 scale set instances were in the restarting stage at a given time. The services in our cluster were also unresponsive during that time. The outage was only a few minutes long, but this seems like something that should not happen.
This is caused by the selected durability level 'bronze'.
The durability tier is used to indicate to the system the privileges that your VMs have with the underlying Azure infrastructure. In the primary node type, this privilege allows Service Fabric to pause any VM level infrastructure request (such as a VM reboot, VM reimage, or VM migration) that impact the quorum requirements for the system services and your stateful services. In the non-primary node types, this privilege allows Service Fabric to pause any VM level infrastructure requests like VM reboot, VM reimage, VM migration etc., that impact the quorum requirements for your stateful services running in it.
Bronze - No privileges. This is the default and is recommended if you are only > running stateless workloads in your cluster.