A virtual data center (VDC) is a software-defined data center that virtualizes compute, storage, and network resources into a single, logical resource pool. VDCs utilize virtualization and cloud technologies to deliver infrastructure services like compute, storage and networking on-demand. This allows enterprises to rapidly provision infrastructure without having to procure physical hardware, making VDCs highly scalable and flexible.
Some key benefits of using a VDC include:
- Agility – Resources can be spun up or down on-demand to meet changing business needs.
- Efficiency – Resources are fully virtualized and shared across workloads leading to high utilization.
- Flexibility – VDCs can be quickly reconfigured to support new applications or workloads.
- Resilience – Services remain available despite hardware failures since VMs can be migrated across hosts.
- Scalability – Additional resources can be quickly added to scale out applications.
VDC architectures bring the automation and flexibility of cloud computing environments within an enterprise data center. Let’s look at the key components that make up a virtual data center.
Key Components of a Virtual Data Center
A virtual data center consists of a software layer known as the VDC manager that provides a unified interface to access and manage compute, storage and network resources. The key components include:
Virtual Compute
The virtual compute layer provides access to a shared pool of host servers that are used to run virtual machines (VMs) and container workloads. Resources like CPU, memory, and disk are allocated from the hosts to VMs in a fully virtualized manner. Popular virtualization platforms like VMware vSphere, Microsoft Hyper-V, RedHat KVM or Docker provide the virtual compute capabilities.
Virtual Storage
Virtual storage refers to storage resources like disks and flash drives that are pooled from multiple storage devices to create consolidated, shared data stores. These are then allocated to provide block, file or object storage services to VMs. Software-Defined Storage (SDS) solutions like VMware vSAN, Microsoft Storage Spaces Direct or open source Ceph help aggregate and manage virtual storage pools.
Virtual Networking
The virtual networking layer provides logically isolated virtual networks to connect VMs within and across physical hosts. This includes services like virtual LANs (VLANs), firewalls, load balancers and virtual private networks (VPNs). SDN solutions like VMware NSX, Cisco ACI or open source Open vSwitch enable building virtual networks that are decoupled from physical network hardware.
Orchestration and Management
VDC managers like VMware vRealize or Microsoft System Center provide a unified interface to control the lifecycle and policies of virtual resources. This includes automating provisioning, monitoring resource usage, implementing governance policies, providing self-service access and orchestrating workflows across infrastructure domains.
Access and Security
End users access services and applications hosted within a VDC through virtual desktops and remoting protocols like VDI and RDP. Identity and access management integration secures access while next-gen firewalls and microsegmentation provide layered network security. Data protection is ensured through backups and DR solutions.
Architecture and Working of a VDC
The architecture of a virtual data center consists of a physical data center layer made up of servers, storage and network devices that provide the resource pool. The virtualization layer contains hypervisors for compute virtualization, SDS for storage and SDN for networking. The VDC management software layer ties together all the resources into unified logical pools. Let’s look at this architecture in more detail:
Physical Data Center Layer
This layer comprises of industry standard x86 servers, hyperconverged nodes, storage arrays (SAN/NAS), and network switches that provide the physical capacity in a data center facility. The servers run hypervisors to create a virtualization layer while storage arrays and switches provide connectivity.
Virtualization Layer
Hypervisors like ESXi, Hyper-V or KVM virtualize the physical server resources to create VMs that are fully isolated from each other. SDS aggregates storage from multiple disks and flash drives into virtual storage pools. SDN provides network virtualization by creating logical overlay networks and network functions like switching, routing, load balancing and firewalls.
VDC Management Layer
The VDC management software leverages the APIs exposed by the virtualization layer to create aggregated logical pools that can be allocated on-demand. For example, vSphere clusters assemble host resources into a virtual compute pool. Similarly, vSAN creates a virtual shared storage pool from multiple physical disks. NSX virtualizes network connectivity between workloads.
The VDC manager provides a self-service portal and service catalog to consume these virtual resources. Additional automation, orchestration and governance capabilities help streamline IT operations. Backup, DR and security services enhance resilience and data protection.
Working and Provisioning
The working of a VDC can be summarized in the following steps:
1. The virtualization layer abstracts physical infrastructure into logical resource pools that can be programmatically managed.
2. The VDC manager leverages APIs to aggregate, allocate and interconnect infrastructure services.
3. The self-service portal allows on-demand provisioning of resources from the shared pools.
4. Additional automation and orchestration streamlines lifecycle management of workloads.
5. Usage is metered, resources are monitored and policies are enforced by the VDC manager.
6. Backup, DR and security enhances resilience and data protection.
When an application owner requests new resources via the VDC portal, the management software allocates the required VMs, storage and networking programmatically from the shared pools. Orchestration engines can help automate the installation, configuration and interconnection of the application. Resources are continually monitored and managed throughout the application lifecycle.
Benefits of a Virtual Data Center
Adopting a VDC-based architecture brings several advantages for enterprise IT:
Agility
Provisioning of infrastructure can be automated and delivered on-demand from a unified portal enabling much faster deployment times. Resources can also be scaled elastically to meet changing workload demands.
Efficiency
Consolidating resources into shared pools drives up utilization while eliminating resource silos. Metering and chargeback models provide transparency into consumption. Policies optimize workload placement and resource sharing.
Resilience
Virtualization provides inherent fault tolerance by isolating failures. Services can be migrated across hosts in case of disruptions. Backups, replication and DR further enhance reliability.
Flexibility
Infrastructure can be quickly reconfigured to changing needs. Services can be composed, interconnected and managed through software. New technologies can be seamlessly integrated.
Scalability
Scale out virtual resources linearly to meet application demands without disruptions. Built-in automation handles repetitive operations. Capacity can be added incrementally.
Security
Software-defined security policies, microsegmentation and next-gen firewalls isolate workloads and secure access. Encryption protects data while backups ensure recoverability.
In summary, VDCs make data center operations highly agile, efficient and flexible while increasing resilience. Enterprises can leverage cloud-like capabilities while retaining control over their infrastructure.
Challenges with Virtual Data Centers
While virtual data centers provide many transformational benefits, there are some potential downsides and challenges to consider:
Complexity
Integrating servers, storage, networks and management software from different vendors can lead to compatibility issues. Careful planning is required to build a unified stack.
Skill Gaps
VDCs require expertise with virtualization, automation tools and converged infrastructure to setup and manage effectively. Retraining or hiring skilled staff is key.
Vendor Lock-in
Proprietary VDC solutions can result in excessive dependence on specific vendors and reduce flexibility in adopting new technologies.
Security Risks
Any exposure in the virtualization layer or VDC software can lead to widespread impact. Strong isolation, segmentation and access controls become critical.
Latency
Abstraction layers can sometimes impose extra latency for storage, networking or compute operations. Performance tuning and infrastructure sizing is important.
Downtime
While failures can be mitigated through migration, maintenance of core VDC components requires careful planning for downtime. High availability configurations add cost/complexity.
Cost
Although hardware consolidation provides long-term savings, the initial switch to a VDC model requires new investments in software and infrastructure overhaul.
While these challenges can seem daunting, proper design, planning and partnerships can help successfully leverage VDCs. The long-term agility and efficiency benefits usually outweigh initial adoption concerns for most enterprises.
Use Cases and Examples
Here are some common use cases and examples of how enterprises are leveraging virtual data centers:
Development/Test Environments
VDCs allow instantly spinning up ephemeral development and testing environments as needed and tearing them down. Shared infrastructure ensures high efficiency and utilization.
Private/Hybrid Cloud
Enterprises are building private and hybrid clouds powered by VDCs to get cloud-like agility. Workloads can migrate between private VDCs and public clouds.
Business Continuity
VDCs facilitate moving or recovering workloads in case of outages or disasters by migrating VMs to alternate sites. Backups can be restored to recreated environments.
Infrastructure Consolidation
Converging siloed resources into a VDC helps retire legacy hardware and reduces sprawl. Optimized sharing drives efficiency.
Remote/Branch Offices
VDCs make it easier to stand up infrastructure at remote offices. Local resources are seamlessly integrated with centralized data centers.
Software-Defined Data Centers
Leading hyper-converged and cloud solutions like VxRail and AWS Outposts are essentially delivering VDC capabilities as on-premises turnkey solutions.
| Company | Use Case | Technology |
|---|---|---|
| VMware | Private cloud VDCs | vSphere, vSAN, NSX |
| Microsoft | Azure Stack hosted VDCs | Hyper-V, Storage Spaces, SDN |
| Nutanix | Hyperconverged VDCs | AHV, Prism, Acropolis |
This table shows some examples of how major vendors provide packaged VDC solutions leveraging their virtualization software stack.
Conclusion
Virtual data centers provide software-defined, unified resource pooling that brings cloud-like agility and efficiency to enterprise data centers. By leveraging capabilities like self-service, automation and orchestration, VDCs can streamline infrastructure provisioning and management. Enterprises stand to benefit in terms of increased speed, flexibility and resilience of service delivery along with better TCO.
While adopting VDCs requires upfront investment and skill building, the long-term rewards are significant. With careful planning and design, the challenges of complexity, security and integration can be effectively managed. Overall, VDCs present a compelling vision of the next-generation, software-defined data center powering digital businesses.