This repo uses a VMSS feature that is in preview currently. Please contact ben.lackey@couchbase.com for assistance. We're expecting GA shortly at which point this will become a non-issue.
Note, if you haven't deployed within the Azure Portal, you'll need to do that to use these templates. Otherwise you'll get an error like this:
error: MarketplacePurchaseEligibilityFailed : Marketplace purchase eligibilty check returned errors. See inner errors for details.
These are Azure Resource Manager (ARM) templates that install Couchbase Enterprise. simple is probably the best starting point. marketplace is the template used in the Couchbase Azure Marketplace offer. generator is a template generator for advanced configurations.
Some best practices are covered here.
Useful links are here.