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Reference Architecture: Architecting for app mobility in a multi-cloud environment.

The need to have a multi-cloud operations model is an area that is gaining mind share as companies look to increase IT operational efficiency across the multiple cloud environments they need to support.   Some reasons companies are adopting a multi-cloud strategy include having the flexibility to:

  • Move apps between more regions/countries than a single provider can support
  • Using differentiated services from more than one cloud provider
  • Relocating workloads from one provider to another when the business strategy dictates the need for such a change

VMware has partnered with all of the major public cloud providers and thousands of service providers to enable organizations to migrate their workloads to any combination of clouds that best supports their needs.  VMware does this in a way that also allows organizations to maintain the same operational model and experience that they have in their on-premises data centers.

Achieving multi-cloud connectivity across multiple cloud providers

When embarking on a multi-cloud strategy, reliable connectivity is critical to achieving high bandwidth, low latency connectivity between on-premises workloads and users, and cloud workloads and services. Each of the major public cloud providers have a direct connectivity option to support this high-quality connectivity requirement. For example, Direct Connect for AWS, Cloud Interconnect for Google and ExpressRoute for Azure.

These cloud providers, delivered and managed options, are ideal when establishing connectivity with a single cloud; but they can add complexity and cost when the organization is looking to establish seamless connectivity between on-premises environments and multiple public clouds.  To mitigate this, organizations also have the option to use non hyper-scaler, third party service provider connectivity options.

Third party, service provider solutions can provide the foundation for routing between multiple public clouds over a dedicated connection.  These options can provide a resilient connection to all the public clouds in use, provide more flexibility around the choice of locations that need to be supported and provide more choices related to the use of lower tier bandwidth options that might be desired in some circumstances.

With the underlaying hybrid connection established, the final piece of the puzzle that must be solved for is determining how to efficiently migrate workloads to the respective clouds in use. This is where VMware HCX can help. VMware HCX provides data deduplication, compression, replication, and extension services to streamline and reduce migration complexity.

VMware HCX is included with most VMware cloud solution offerings, easing the decision of what tool to use to migrate applications between clouds. When a customer is leveraging a VMware, partner delivered multi-cloud connectivity option, a separate HCX Service Mesh is deployed on premises for each public cloud SDDC that is a target for application migrations. The HCX Service Mesh deployments on-premises will then trigger the deployment of HCX Service Mesh components on the respective VMware SDDC deployed on a public cloud or managed service provider environment.

With HCX installed and deployed, portability of your VMware-based workloads from on-premises environments to the public cloud as well as for “cloud to cloud” migrations are greatly simplified. For example, a workload that was originally developed in an on-premises vSphere environment can be live-migrated to a VMware Cloud on AWS environment via HCX.  The same is true for each of the major hyperscale public clouds and managed service provider partners that support deployment of a VMware SDDC.

Reference architecture for multi-cloud connectivity and app mobility

For organizations looking to establish multi-cloud app portability, our team has created a “multi-cloud app portability reference architecture” (figure one).  You can download a PDF of this architecture here.

Figure 1:  Architecture for establishing multi-cloud connectivity


From a high-level perspective, to support connectivity for multi-cloud application mobility, your organization will need to:

  • Establish dedicated multi-cloud connectivity using your selected multi-cloud networking partner or partners starting with your on-premises data center.
  • Configure the dedicated connection from the partner multi-cloud provider to all the respective cloud environments targeted for use. Refer to the partner and cloud provider documentation for the requirements and procedure details.
  • Deploy VMware SDDCs within the respective cloud providers, with non over lapping IP address space for SDDC Management and application workload networks.
  • Open the required HCX firewall ports in the on-premises firewall and the cloud side firewalls; allow HCX Manager communication over TCP port 443; allow HCX Interconnect and Network Extension traffic over UDP port 4500.
  • Download and deploy HCX Connector Appliance on premises (make sure HCX is also deployed on cloud SDDC if not automatically deployed with the creation of SDDC). Once the HCX Connector is deployed, activate and pair the Connector with the on premises vCenter.
  • Login to the on premises vCenter, navigate to the HCX plugin, configure site pairings from on premises to each cloud HCX Manager, then configure the Compute and Network Profiles for the respective resources on prem.
  • Next deploy the required HCX Service Mesh(s) to connect to the respective VMware SDDCs located within each cloud provider. This will deploy the respective service mesh appliances on the cloud SDDCs.


With the successful deployment of each Service Mesh, the customer is ready to begin the planning and execution of migrations of application workloads to the cloud SDDC that fits the requirements of users and applications.

Summing up

With a partner connectivity model established and VMware HCX deployed, customers can execute on the required migration activities outlined based on completed migration planning that includes the assessment of application dependencies and organized application move groups.

Learn more

Interested in learning more about how VMware can help you architect a multi-cloud solution for your organization.  Check out these two resources:

  • Looking to better understand VMware’s unique approach to multi-cloud architecture? Get the definitive guide
  • VMware Multi-Cloud Podcast: This Podcast series on SoundCloud interviews VMware technical leaders and explores how VMware Cloud offerings can help you architect a multi-cloud environment that accelerates application modernization across a multi-cloud landscape.
  • VMware Cloud on AWS Reference Architectures: This collection of reference architectures details how to deploy various application and hardware stacks in a hybrid cloud model that includes VMware and AWS technologies.


My thanks to Joe Mann and Jeffrey Moore. The blog system only allows for one author of record but both Joe and Jeffrey contributed substantially to this reference architecture and blog post.