VMware operates as a Type-1 or “bare metal” hypervisor, which means it runs directly on the host’s hardware rather than within an operating system. This allows it to access hardware resources more efficiently compared to Type-2 hypervisors.
A hypervisor, also known as a virtual machine monitor (VMM), is a software, firmware, or hardware component that creates and manages virtual machines (VMs) on a host computer. It enables multiple operating systems to run simultaneously on a single machine through a process called hardware virtualization.
There are two main types of hypervisors:
Type-1 or “bare metal” hypervisors
These run directly on the host’s hardware, effectively replacing the host operating system. Because they don’t have to go through an intervening software layer, Type-1 hypervisors can provide more efficient access to critical I/O resources like storage and networking to help maximize performance. Both VMware ESXi and VMware vSphere Hypervisor (ESXi’s free counterpart without advanced features) are Type-1 hypervisors.
Type-2 or “hosted” hypervisors
These run as software within a conventional operating system environment. For example, VMware Workstation Pro and Oracle’s VirtualBox both operate as hosted hypervisors. Since they utilize existing OS resources, Type-2 solutions have higher overhead and slightly lower performance, but they are convenient to set up and run for many non-critical workloads.
On bare metal, hypervisors can directly access underlying hardware resources without going through an intervening OS layer. Type-1 solutions like VMware ESXi can boot directly onto the server hardware instead of being installed into an operating system like a conventional application.
Advantages of VMware’s approach
VMware’s Type-1 or bare metal approach enables it to provide several key advantages for virtualization in data centers and enterprise settings:
- Better performance and efficiency: Without an intervening OS layer, VMware hypervisors have lower overhead and can access hardware more directly. This helps maximize resource sharing for superior performance.
- Greater stability and reliability: The smaller code base and lack of dependence on an OS enhances reliability. There is less patching/upgrading since the hypervisor layer does not have to coordinate changes with a parent OS.
- Improved security: The reduced attack surface and isolation from vulnerabilities in a general-purpose OS enhances security. The hypervisor helps ensure strict isolation and allocation of resources between VMs.
- Easier scalability: With direct hardware access, VMware solutions can better leverage resources across larger clusters as infrastructure scales. This makes it simpler to dynamically allocate resources to meet workload demands.
- Robust ecosystem support: VMware garners strong third-party integration and support since it is a trusted enterprise platform leader as a Type-1 solution. ISVs and hardware vendors routinely optimize offerings for VMware.
How VMware’s hypervisor works
VMware products rely on a proprietary bare metal hypervisor architecture. VMware ESXi/vSphere Hypervisor interacts with physical servers in several key ways:
1. Direct installation on host hardware
VMware products install directly on the server hardware, effectively replacing the host operating system that would normally manage resources.
2. Virtualization of physical resources
The hypervisor inserts a lightweight software layer that takes physical CPUs, memory, storage and more to create virtual resources.
3. Allocation to virtual machines
These virtualized hardware resources are then allocated dynamically and safely to multiple guest VMs constructed by the hypervisor.
4. Virtual hardware drivers
Virtual machines access assigned resources using drivers for virtual devices like vNICs and vDisks instead of physical hardware drivers.
5. Host OS/management VM options
While the core hypervisor has a compact footprint, VMware also utilizes specialized host OS/management VMs for additional control, automation and administrative access.
This architecture allows the hypervisor layer to safely share host hardware as “virtual” resources allocated to isolated VMs running various operating systems. Workloads in VMs carry on without modification, unaware they operate on virtual rather than physical hardware.
VMware product portfolio
VMware offers an extensive product portfolio leveraging its bare metal hypervisor technology:
- vSphere Hypervisor: Free bare-bones hypervisor for basic server virtualization needs
- VMware ESXi: Robust standalone hypervisor forms foundation for vSphere data center virtualization platform
- vSphere: Suite of tools & services to manage VMware hypervisors and infrastructure
- vCenter Server: Centralized management, automation and analytics for monitoring large vSphere deployments
- VMware Cloud Foundation: Integrated hybrid/multi-cloud platform spanning both virtualized and containerized workloads
- VMware Cloud: VMware’s wide portfolio of SaaS solutions for managing multi-cloud needs
- VMware Tanzu: Supports modern application development leveraging containers, microservices and Kubernetes
- VMware NSX: Network virtualization and SDN solution works across VMware environments
- VMware vSAN: Hyperconverged infrastructure for software-defined storage built into the hypervisor
And many more products and tools that take advantage of capabilities in VMware’s bare metal hypervisor!
- VMware utilizes a Type-1 or “bare metal” hypervisor that runs directly on server hardware without an intervening operating system.
- This provides performance, efficiency, reliability and security advantages compared to hosted Type-2 solutions.
- Key capabilities include:
- Direct access to hardware without overhead
- Resource allocation to VMs using virtualization
- Support for many OS environments in guest VMs
- Management components for control, automation & analytics
- VMware provides an extensive suite of offerings leveraging its hypervisor technology for full-stack, multi-cloud environments.
In conclusion, VMware operates as a Type-1 or bare metal hypervisor, running directly on host hardware. This approach is beneficial for enterprise usage because it maximizes performance without an intervening operating system while also enhancing stability, security and scalability. It enables the efficient allocation of virtualized hardware resources to multiple guest VMs in data center and cloud environments. VMware has extended capabilities enabled by its hypervisor into an extensive product portfolio today that spans virtualization, SDN, storage, security and cloud management.
Frequently Asked Questions
- What is the key benefit of a Type-1 hypervisor?
The main benefit of a Type-1 or “bare metal” hypervisor is that it runs directly on server hardware, eliminating dependence on a host operating system and the associated overhead. This allows for more efficient utilization of server resources.
- Is VMware’s hypervisor free?
Yes, VMware offers the free, standalone ESXi hypervisor known as vSphere Hypervisor for basic servers. The full VMware vSphere product suite adds advanced management capabilities on top of the base ESXi hypervisor layer.
- What hardware does VMware’s hypervisor run on?
VMware’s ESXi hypervisor supports industry-standard x86 server hardware from the likes of Dell, Cisco, HPE and Lenovo as well as hyperconverged infrastructure such as VMware vSAN ready nodes.
- Does VMware support Linux VMs?
Yes, VMware’s hypervisor can run various Linux distributions like RHEL, CentOS, Ubuntu and SLES as guest VMs alongside Windows and other operating systems.
- Can you virtualize containers with VMware?
Yes, VMware provides container support and Kubernetes orchestration in solutions like vSphere with Tanzu. Containers can run alongside virtual machines using the VMware hypervisor and infrastructure.
- Is VMware hypervisor only for on-premises use?
No. Increasingly, the VMware software-defined data center stack is offered by major public cloud providers. These enable VMware workloads to run on AWS, Azure and Google Cloud leveraging the same hypervisor.
- What is vMotion and how does it work?
vMotion is VMware’s live migration technology for moving running VMs across hosts without disruption. It works by using the hypervisor layer to shift VMs while retaining VM identities like MAC addresses.
- Is VMware hypervisor difficult to manage?
No. VMware vCenter provides centralized, intuitive management and automation across VMware infrastructures and hypervisors. Command line access is also available.
- How are resources allocated to VMs in a VMware hypervisor?
The VMware hypervisor automatically allocates available physical CPU cores, RAM, storage capacity and I/O bandwidth to create “virtual” hardware that is assigned safely to each provisioned VM.
- Does VMware support hyper-threading?
Yes. VMware’s hypervisor can take advantage of Intel’s hyper-threading capabilities to further increase the number of virtual CPUs supported per physical core when needed.
- Can I live migrate VMs across different hypervisors?
Unfortunately live migration is generally only supported when moving VMs between the same hypervisor platforms due to compatibility issues. Migrating workloads across hypervisors involves offline methods.
- Does the VMware hypervisor support graphics acceleration?
Yes. Newer VMware versions support virtual GPU allocation for graphics/compute intensive VMs leveraging physical NVIDIA or AMD GPUs. Technologies like vSGA allocate portion of GPU resources to VMs.
- How does vSphere differ from the vSphere Hypervisor?
VMware vSphere is the product suite that includes the vSphere Hypervisor ESXi along with advanced management and automation capabilities via vCenter Server and tools. vSphere Hypervisor is the free standalone hypervisor.
- Does VMware provide formal training courses?
Yes. VMware offers many authorized training and certification courses covering topics like installing, configuring, managing and troubleshooting their solutions including the vSphere hypervisor component.
- What is VMware Cloud Foundation?
VMware Cloud Foundation is an integrated hybrid cloud platform that combines the hypervisor-driven software-defined data center capabilities of vSphere with simple deployment of cloud-native capabilities leveraging containers and Kubernetes
- Does VMware solely focus on virtualization?
No. While virtualization powered by their hypervisor remains a core focus, VMware also provides capabilities around SDN, storage, app modernization, security and multi-cloud management among other emerging solutions.
- What major competitors does VMware have?
Leading competitors in the virtualization and multi-cloud space includes Microsoft Hyper-V, Citrix XenServer, Red Hat Virtualization and Nutanix Acropolis for hypervisors, as well as AWS, Azure, OpenShift and more for cloud platforms.