What does 'built' mean? How were those 86 instances 'built'?
Azure is a virtual operating system for hosting *guest* operating systems - which could be Linux (any flavor) or Windows - competitors (actually leaders): Amazon and Google.
Other (leaders in) virtual services from Amazon as an example, offer EC2's but with various options for cores, memory, space and of Ubuntu, CentOS, etc. And they also offer storage virtual machines as well as dedicated DB servers.
Google ... same thing ... have a one button click install of CentOS 7.1 minimal upon which I've installed PHP 7 and am using MariaDB 10.1 ... with a Moodle 3.1 (not bragging just providing an example).
So are all 86 of the instances you have 'built' on ???? operating system on a single guest OS?
OR do you have 86 separate Azure hosted guest OS's of X 'built' - each of the 86 having their own web server (IIS or Apache), DB server, with PHP X, etc..?
Since you've already said they are 'built' ... installation of each instance of a Moodle would have required the setup of a web server, a DB server, etc and they must already have DNS (FQDN). So it sounds like you now plan to 'migrate' 86 instances from their currently hosting situation to these 86 'built' Moodles. IF that's true ... we're talking just migrating and not migrating and upgrading at the same time, are we?
86 instances of Moodle on *one* operating system where not only the web services reside but also the DB's for those 86 + the moodledata directories for those 86 instances has to be one hoss of a box.
'spiriit of sharing', Ken