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We have a 2 server instance Azure Cloud service and during an automatic update on the servers, sometimes the restarts between the different servers are so close together that the service becomes temporarily unavailable or times out.

example: Server1 : restarted at 1:30pm, web application starts at 1:35, services are stable after .net compilation at around 1:38

Server2 : restarted at 1:35pm, web application starts at 1:40, servers are stable after .net compilation at around 1:43

given the above scenario, there is a "downtime" on the service availability between 1:35-1:38pm while Server1 is ramping up.

Is there a way to increase the gap between the server restarts?

eugenecp
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  • Are the services in the same availability set? – Drifter104 Oct 07 '16 at 21:51
  • They are in different upgrade domains/availability set. – eugenecp Oct 07 '16 at 21:53
  • They should be in the same set https://azure.microsoft.com/en-gb/documentation/articles/virtual-machines-windows-manage-availability/#configure-multiple-virtual-machines-in-an-availability-set-for-redundancy – Drifter104 Oct 07 '16 at 23:19
  • Yeah it might just be thehe wording you use, but they should be in the same availability set but in different fault and upgrade domains. – Sam Cogan Oct 08 '16 at 08:41
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    Common issues #5. https://blogs.msdn.microsoft.com/kwill/2012/09/19/role-instance-restarts-due-to-os-upgrades/ – Bruno Faria Oct 08 '16 at 14:08
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    drifter104 sorry I meant same availability set, different upgrade domains, thanks sam. @bruno thanks for the link, we will look at the OnStart option. – eugenecp Oct 09 '16 at 02:07

1 Answers1

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In brief, to my knowledge, there is no way to increase the gap between the server restarts.

But we can add a VM to the availability set to ensure that at least one virtual machine will be available. Because the default available set has two fault domains and five update domains. So add the VM to the availability set, the VM will be create in the different update domain, during an automatic update on the servers, the availability set to make sure your service doesn’t go offline because of an update, it will walk through your update domains one after the other.

You can see that in the following screen shot of a collection of 12 VMs in a single availability set: enter image description here

If you still have questions, welcome to post back here. Thanks.

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Jason Ye
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