Decom notice for A8-A11 vms on 3 docs

Author: Julia Shimanskiy

articles/virtual-machines/sizes-general.md

@@ -35,6 +35,9 @@ General purpose VM sizes provide balanced CPU-to-memory ratio. Ideal for testing
 
 Example D-series use cases include enterprise-grade applications, relational databases, in-memory caching, and analytics.
 
+> [!NOTE]
+> The A8 – A11 VMs are planned for retirement on 3/2021. For more information, see [HPC Migration Guide](https://azure.microsoft.com/resources/hpc-migration-guide/).
+
 ## Other sizes
 
 - [Compute optimized](sizes-compute.md)

articles/virtual-machines/sizes-hpc.md

@@ -42,6 +42,10 @@ Azure H-series virtual machines (VMs) are designed to deliver leadership-class p
   
 - **Virtual network** – An Azure [virtual network](https://azure.microsoft.com/documentation/services/virtual-network/) is not required to use the compute-intensive instances. However, for many deployments you need at least a cloud-based Azure virtual network, or a site-to-site connection if you need to access on-premises resources. When needed, create a new virtual network to deploy the instances. Adding compute-intensive VMs to a virtual network in an affinity group is not supported.
 - **Resizing** – Because of their specialized hardware, you can only resize compute-intensive instances within the same size family (H-series or compute-intensive A-series). For example, you can only resize an H-series VM from one H-series size to another. In addition, resizing from a non-compute-intensive size to a compute-intensive size is not supported.  
+
+> [!NOTE]
+> The A8 – A11 VMs are planned for retirement on 3/2021. For more information, see [HPC Migration Guide](https://azure.microsoft.com/resources/hpc-migration-guide/).
+
 ## RDMA-capable instances
 
 A subset of the compute-intensive instances (A8, A9, H16r, H16mr, HB and HC) feature a network interface for remote direct memory access (RDMA) connectivity. Selected N-series sizes designated with 'r' such as the NC24rs configurations (NC24rs_v2 and NC24rs_v3) are also RDMA-capable. This interface is in addition to the standard Azure network interface available to other VM sizes.

articles/virtual-machines/sizes-previous-gen.md

@@ -165,6 +165,9 @@ The A8-A11 and H-series sizes are also known as *compute-intensive instances*. T
 
 <sup>1</sup>For MPI applications, dedicated RDMA backend network is enabled by FDR InfiniBand network, which delivers ultra-low-latency and high bandwidth.  
 
+> [!NOTE]
+> The A8 – A11 VMs are planned for retirement on 3/2021. For more information, see [HPC Migration Guide](https://azure.microsoft.com/resources/hpc-migration-guide/).
+
 <br>
 
 ### D-series