Change number of upgrade domains in Azure Service Fabric

4
votes

In Azure Service Fabric, the default number of upgrade domains is 5. Is there a way to change to a different number?

From https://docs.microsoft.com/en-us/azure/service-fabric/service-fabric-cluster-resource-manager-cluster-description#configuring-fault-and-upgrade-domains, there's ClusterManifest.xml, but it doesn't seem we should modify it.

1
azureazure-service-fabric

1 Answers

1
votes

This is not possible in Azure today. SF picks up the FD and UD information from the VM Scale Sets that it runs on, and today these are capped/locked at 5x5. SF itself doesn't care how many UDs you have, and generally recommends more so that during an upgrade you're taking down less of your overall service in terms of capacity and also have more time to react to any issues.

There are some workarounds:

  • Run multiple service fabric application instances. Since each application instance is independently upgradable, you end up with (app instances) * (# of UDs) separate upgrade boundaries
  • Run the cluster across VM Scale Sets in multiple Azure AZs
    • Unfortunately this only works in areas where Azure has multiple AZs exposed