Extending Layer 2 Networks into AWS with Hybrid Cloud Extensions (HCX)

Introduction

This article will guide you through creating an Extended Network with Hybrid Cloud Extension (HCX). HCX allows customers to easily move workloads from on-premises into AWS, with minimal change and in some case no downtime. One feature of HCX is the Network Extension feature, this allows customers to stretch their Layer 2 networks from their on-premises data center to AWS, making it possible for virtual machines (VMs) to retain their IP and MAC addresses when they are migrated to AWS. This eliminates the need to re-IP VMs, reconfigure network settings, or change application IP addresses, which simplifies the migration process and minimises downtime.

If you have not deployed HCX, please refer to my post Hybrid Cloud Extension (HCX) Install Guide for VMware Cloud on AWS.

Prerequisites

One of the main prerequisites for leveraging the Network Extension service in HCX, is the to have a vSphere Distributed Switch (VDS) on-premises. If you don't have a VDS and are leveraging VMware Standard Switches , and still need to extend Layer 2 networks into AWS, then you can look at other Layer 2 connectivity options.

Please review the full list of Restrictions and Limitations for Network Extension to ensure you environment meets all the requirements.

Instructions - How to Extend Layer 2 Networks using HCX

1. Log into your on-premises (or source) vCenter
2. In the menu, select HCX
3. From the HCX menu, select Network Extension

4. In the Network Extension window, select + Extend Networks

5. Select the Service Mesh, if you only have one Service Mesh, this Service Mesh will be the default option
6. Select the Source Network you want to Extend, select Next
7. Select the Destination First Hop Router, in most cases this should be the Compute Gateway
8. Provide the Gateway IP address and Prefix Length for the network being extended (Example: 192.168.10.1/24)
9. Choose the Extension Appliance (if you only have one extension appliance, this will be the default. You can have multiple Network Extension Appliances, each appliance can extend up to 8 networks)
10. Select Mobility Optimised Networking if required

Note: Mobility Optimized Networking (MON) improves traffic flows for migrated virtual machines by enabling selective cloud routing (within the SDDC), avoiding a long round trip network path via the on-premises gateway. This feature is available in all VMware Cloud on AWS deployments. There are a number of caveats when using MON, please review these here. 11. Overlapping VLANs is an optional setting, and should only be selected if required. HCX prevents you from extending networks that have the same VLAN ID and Gateway IP address. Select Allow Overlapping VLANs to override this setting. 12. Click Submit

Allow for up to 5 minutes for the Extended Network to be created, you should see the Extended Network being created and once complete it will have a green tick in the status column. In the example below I have multiple Extended Networks.

Instructions - Review the Extended Network in VMware Cloud on AWS

Once the Extended Network has been created, it will be visible in the VMware Cloud on AWS console.

1. Log into the VMware Cloud on AWS Console
2. Select your Software Defined Data Center (SDDC), then select on the Networking & Security tab
3. Select Segments (under the Network heading)

The newly created Extended Network segment will have the naming convention starting with L2E_, you can change this by click on the ellipsis and selecting Edit. You will also see that the Extended Network has Disconnected under the column Connected Gateway, this is how HCX Extended Networks will appear, if you enable MON, these Extended Networks will show up slightly different, as you can see below the Extended Network shows MON and shows as Routed under the Connected Gateway column.

Conclusion

In this article you have learnt how to extend layer 2 networks into AWS, this allows you to easily migrate on-premises workloads into AWS with minimal networking changes.