System Center App Controller 2012 R2 is a self service portal which can be used to deploy virtual machines on on-premise clouds managed by System Center Virtual Machine Manager, Service Provider Clouds using Windows Azure Pack and Windows Azure.
Windows Azure offers so called t-shirt sized virtual machines. These have a Microsoft determined number of virtual cores and virtual memory size. The size of virtual machines is identified as extra small, small, large etc. Recently Microsoft started to offer large sized virtual machines which are identified as A5, A6 and A7.
Using App Controller 2012 R2 the virtual machine / instance size A5 , A6 and A7 are missing in the dropdown list showing available virtual machine sizes for deployment.
This is caused by a limitation of App Controller 2012 R2. App Controller maintains a hard coded list of virtual machine sizes that it is able to deploy. A5, A6 and A7 are not in that list. Future new instance sizes available in Azure will not available either as long as the code of App Controller is not updated by Microsoft. This issue is caused by the service management API which is queried by App Controller. This API does not allow to query for available virtual machine sizes hence the hardcode virtual machine sizes.
Virtual machines sized A5, A6 or A7 can be managed by App Controller. Deployment however of instances with these sizes should be done using the Azure Management Portal, Visual Studio, Azure command-line tool or PowerShell.