CODEWITHSUNDEEP
azure-service-fabric
BrettRobi
BrettRobi

Reputation: 3921

Windows OS Update/Patch handling - best practices for SF today

I'm aware that the SF doesn't yet automatically handle OS Upgrades/patching in any way like Cloud Services do. I eagerly await it when that is ready. But for now I am curious what I should expect by default.

Since SF uses Scale Sets and standard Windows VMs, should I expect that the instances will have the default Windows Update settings and thus will reboot automatically every so often as updates are applied? I believe the defaults are to install updates automatically and reboot during the defined maintenance window (3am?), is that correct?

If that is true, can I expect that SF will gracefully handle the reboot? By that I mean any services running on it are shutdown and the load balancer is notified to stop sending requests to any externally visible endpoints on that host?

But taking that a step further, if all of the above happens to be true, is there anything preventing all nodes in my cluster to hit the maintenance window and reboot at the same time? That would seem catastrophic to me.

Given all that, what is the best practice and general advice for handling Windows Updates in SF today?

Upvotes: 3

Views: 468

Answers (1)

Todd Abel
Todd Abel

Reputation: 439

You're correct that there could be catastrophic results if you just turn on Windows Update and let it go. There will be no coordination when the node reboots and you could lose part or all of your application or cluster if the nodes cause the service fabric services to lose quorum.

The only safe approach is to install the patches/updates on a single node at a time and don't move to the next node until the cluster is healthy. This can be scripted to make it easier or worst case can be done manually.

There may be another approach that has to do with adding nodetypes, but it is not yet tested, so I don't want to give details until we know it works.

Upvotes: 2

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