Cloud Migration Series: Part 2 – VMware HCX Overview

In Part 1 of our Cloud Migration series, we discussed traditional migration methods – Cold Migration and vMotion – and their requirements. This gives you the ability to migrate virtual machines to the cloud with the same technology you use on-premises every day, sometimes without even thinking about it. In Part 2 we are going to discuss the third method of migration, which utilizes VMware HCX, and how this will provide additional features and flexibility to successfully migrate virtual machines into VMware Cloud on AWS.


What is it?

VMware HCX is a workload mobility platform – a migration tool that abstracts both on-premises and cloud resources and presents them as a single, fluid, resource for applications to consume. To put it another way, it allows for bi-directional migration of virtual machines from one location to another with (almost) total disregard for disparate vSphere versions, virtual networks, connectivity, etc. It does this by creating a secure, high performance, overlay that includes WAN optimization, load balancing, and VPN with Suite B encryption between your on-premises data center and your Cloud SDDC. This is made possible through a handful of appliances deployed at each location.


That’s great, but what does all of that REALLY mean?

  • It means you can migrate virtual machines in bulk instead of one at a time.
  • It means you can kick off a migration right now or schedule your migrations for a different date/time (like Sunday morning at 02:00).
  • It means you can migrate VMs from unsupported vSphere 5.x (and soon 6.0) without having to go through an upgrade process.
  • It means you can migrate VMs off of old virtual switches like Cisco Nexus 1000v.
  • It means you can upgrade VM Tools, Virtual Hardware, or even force unmount ISOs as part of the migration process.


Not only does VMware HCX let you migrate virtual machines from on-premises to the cloud, but also between on-premises locations, and Cloud to Cloud (C2C).


HCX Dashboard



VMware HCX is comprised of a group of appliances. These are deployed automatically for you with the single click of a button when using VMware Cloud on AWS. Afterward you’re provided download links for the on-premises components that need to be deployed.

HCX Appliances

HCX Manager

Deployed next to the vCenter Server. There are two types of managers: Cloud and Enterprise. Cloud is deployed by the cloud provider, whereas Enterprise is deployed by the customer on-premises. The HCX Manager is where the administration and configuration of HCX takes place. All other HCX components (services) within the HCX Service Catalog are deployed through the HCX Manager.


HCX Interconnect (HCX-WAN-IX)

Provides replication and vMotion migration capabilities over the internet and private lines to the HCX target site with strong encryption and traffic engineering.


HCX WAN Optimization (HCX-WAN-OPT)
Provides line conditioning and data de-duplication to create LAN-like performance across to the cloud using a VPN without the need for AWS Direct Connect (DX).


HCX Network Extension (HCX-NET-EXT)

Provides secure Layer 2 extension capabilities (VLAN, VXLAN, and Geneve) for vSphere or 3rd party distributed switches and allows the virtual machine to keep the same IP and MAC address during migration. Essentially, we’re extending Layer 2 from on-premises to VMware Cloud on AWS to help your migrations remain seamless.


HCX Sentinel Gateway (HCX-SGW)

If the need arises to migrate non-vSphere guests such as KVM or Hyper-V based virtual machines, the SGW allows for connecting and forwarding the guest workloads between the Sentinel software installed on the virtual machine and the Sentinel Data Receiver in the target environment.


HCX Sentinel Data Receiver (HCX-SDR)

The SDR works in conjunction with the Sentinel Gateway to receive, manage, and monitor data replication operations at the destination environment.


HCX Appliance View


Advanced vs Enterprise

The HCX features available to you are based on the type of license you’re using. VMware HCX Advanced comes packaged with NSX Datacenter Enterprise Plus, VMware Cloud on AWS, VCF Enterprise, and from various VMware Cloud Provider Partners (VCPPs). VMware HCX Enterprise is an additional license available for purchase that you can add on to your existing licensing.


VMware HCX Advanced provides:

  • HCX Interconnect Services
  • WAN Optimization
  • Network Extension
  • Bulk Migration
  • vMotion Migration
  • Disaster Recovery

VMware HCX Enterprise provides these additional features:

  • OS Assisted Migration (OSAM)
  • HCX vMotion with vSphere Replication also known as Replication Assisted vMotion (RAV)
  • Site Recovery Manager Integration for Disaster Recovery


Migration Options

There are five migration options available when using VMware HCX.


Cold Migration

This method is similar to a cold migration initiated via the vSphere Client. It’s simply a Network File Copy (NFC) of the VM to the target site through the same network path an HCX vMotion would use. It’s automatically used for any powered off virtual machine migration.


HCX vMotion

HCX vMotion is the ability to transfer a live VM between HCX enabled sites capturing the active state of the VM in its entirety. The bonus to HCX vMotion is the additional compatibility it provides allowing migration from vSphere 5.5 – 6.7+, hardware v9+, migration without EVC, and it works with isolated and overlapping vMotion subnets.


HCX Bulk Migration

Bulk migration uses host-based replication (HBR) to move a live virtual machine. This is accomplished by replicating the virtual machine (seeding) to the target site. Once an initial full sync is completed, delta synchronization begins. Once the delta is complete, a switchover is triggered. Note that the VM stays online during the replication process up until the switchover. The switchover can be done immediately or scheduled for a specific date/time. Scheduling the switchover is ideal for maintenance windows. When the switchover occurs, the VM is powered off, and the replica is powered on. If there is a problem with the new VM powering on, the original VM will be powered back on. VMware HCX renames the powered off VM in the source site and appends a binary timestamp to the VM name. The original VM is then moved into a new folder called “Migrated VMs” to help avoid any confusion.


HCX vMotion with vSphere Replication

Replication Assisted vMotion takes your migration to the next level by combining HCX Bulk Migration with HCX vMotion. This provides parallel operations, resiliency, and scheduling, with host-based replication for zero downtime VM migrations.


OS Assisted Migration (OSAM)

As with RAV, OS Assisted Migration also requires HCX Enterprise licensing. It uses Sentinel software that is installed on the Linux or Windows-based guests. The Sentinel software obtains the guest configuration and assists with the replication to the destination through the Sentinel Gateway to the Sentinel Data Receiver. This migration type is ideal for moving virtual machines from non-vSphere environments such as KVM or Hyper-V. Similar to a bulk migration, the VM remains online during the replication process. Once initial replication is completed, HCX performs a hardware mapping, driver installation, and OS configuration for the new vSphere virtual machine, and reboots the VM. After the VM is rebooted, a delta sync is kicked off, and the switchover is triggered. VMware Tools is installed on the migrated virtual machine as a final step.


HCX Migration Wizard

Additional Options

The HCX interface also provides a set of options that can be applied pre or post-migration depending on method and behavior. These options include:

  • Force Power-Off VM
  • Retain MAC
  • Upgrade Virtual Hardware
  • Upgrade VM Tools
  • Remove Snapshots
  • Force Unmount Container
  • Select Destination Container
  • Select Destination Storage
  • Select Virtual Disk Format
  • Select Destination Network


Migrating workloads to the cloud might seem daunting, but VMware HCX aims to add flexibility and simplify the process while maximizing uptime. Stay tuned for Part 3 where we’ll dive into VMware HCX just a little bit further and discuss the anatomy of the Service Mesh.


Cloud Migration Series


Part 1: Getting Started with Hybrid Cloud Migration
Part 2: VMware HCX Overview
Part 3: The HCX Interconnect and Multi-Site Service Mesh
Part 4: Planning and Considerations