You are developing a Microsoft Azure web application. The application will be deployed to 10 web role
instances. A minimum of 8 running instances is needed to meet scaling requirements.
You need to configure the application so that upgrades are performed as quickly as possible, but do not
violate scaling requirements.
How many upgrade domains should you use?
A.
1
B.
2
C.
5
D.
10
why 5 ?
That is the default:
A fault domain is automatically assigned by Windows Azure. You need at least two instances spread across two fault domains to have maximum availability guaranteed by Windows Azure.
By default, you have a maximum of five update domains. You can control how many up-
grade domains you have by using the upgradeDomainCount attribute in your ServiceDefinition configuration file. You can have a maximum of 20 upgrade domains.
So Fault Domains (allow) come in sets of 2 (10 – 8 = 2) and Upgrade Domains come in sets of 5 (default) !!
See https://docs.microsoft.com/en-us/azure/cloud-services/cloud-services-update-azure-service
The default 5 of upgrade domains does not matter. Azure updates a cloud service one Upgrade Domain at a time. A minimum of 8 running instances is needed to meet scaling requirements. So, you must update only 2 (=10-8) web role instances at a time. And you should split your 10 instances to 5 (=10/2) groups – Upgrade Domains.
give this man a cookie. I would add: you should split your 10 instances into 5 groups (2 instances per group).