The Hypervisor

1: The Hypervisor is the software responsible for monitoring and controlling virtual machines or guest OSes. In addition, the hypervisor/VMM is accountable for providing different virtualization management tasks.

2: Such tasks may include providing virtual hardware, virtual machine life cycle management, migrating virtual machines, allocating resources in real-time, and defining policies for virtual machine management, to name a few.

3: This carries many benefits, such as running multiple guests operating on the same physical system or hardware. Furthermore, these guest systems can be on the same OS or different. In terms of types, we can categorize hypervisors as either type 1 or 2.

**Test and Develop**

– One of the primary benefits of nested hypervisors is the ability to test and develop virtualization environments without needing additional physical hardware. Running a hypervisor within a virtual machine allows one to create and manage multiple virtual machines, each with its unique configuration and operating system.

– Another use case for nested hypervisors is in cloud computing. Cloud service providers often use nested virtualization to provide their customers with virtual machines that can run their hypervisors. This gives customers complete control over their virtualization environment, enabling them to run their virtual machines and manage them as they see fit.

– Furthermore, nested hypervisors can be used for teaching and learning purposes. They provide a safe and isolated environment for students and professionals to experiment with different virtualization setups without the risk of affecting the underlying hardware. This allows for hands-on experience and the exploration of various virtualization technologies.

– Despite the many benefits of nested hypervisors, some considerations must be considered. Since each layer of virtualization adds additional overhead, performance can be impacted. The more levels of nesting, the more resources are required to maintain the virtualization environment. It is essential to consider the hardware resources available carefully and the workload requirements before implementing nested hypervisors.

Nested hypervisors and public cloud agnostic

It would help if you aimed to make the public cloud easy to consume on demand. You are saying enterprises to replicate all on-premise infrastructure to the cloud without changing the internal application structure and infrastructure. It operates by snapping a blueprint of what you have on-premise and then copying that “file” to Ravello’s cloud network, which lies on Amazon and Google (no support for Azure yet). For example, you may have a 3-tier application stack load balanced with Netscaler and secured by Fortinet and Paolo Alto.

Each tier requires clustering with non-routable packets. Ravello’s technology allows you to take a blueprint of the tiers and support infrastructure and replicate it to the cloud. Their solution allows enterprise data center applications to benefit from elastic and agile cloud benefits without changing the application. How does all this work?

Overlay Tunnels & Nested Hypervisors 

Ravello nested hypervisor solution is a software-as-a-service (SaaS) cloud services provider, a cloud that sits on top of other clouds. Ravello utilizes existing public clouds to seed its cloud by deploying a cloud to another cloud. Their ability to provide a clean layer 2 environment comes from constructing point-to-point overlays using User Datagram Protocol (UDP) as the transport.

Ravello is powered by a new HVX nested hypervisor and Software-Defined Networking (SDN). Its distributed hypervisor combines software-defined overlay networking and a nested virtualization engine. The nested hypervisor approach allows customers to bring their network elements (e.g., Juniper or Cisco router, F5 or NetScaler load balancer, and various firewall appliances ) to implement a chosen network function and topology.

**Full overlay solution**

Ravello implements a complete overlay solution that exposes clean Layer 2 networking to the guest. Now, you can use any networking feature; multicast, broadcast, VLAN, VMAC, GARP, and span ports, giving access to all functionality initially available with on-premise data centers. It’s similar to buying a Virtual Private LAN Service (VPLS) from a managed Service Provider. With VPLS, you can design any topology.

However, by default, public clouds are not network-ready and have limited complex topology support, mainly due to the lack of Layer 2. With Ravello, you can have full layer 2 and 3 flexibility in Amazon and Google’s public cloud.

Their network overlay consists of a data plane and a control plane element. The control plane comprises a distributed Layer 3 router and other DNS / DHCP features. A Data plane is a fully distributed virtual switch and virtual router. With an overlay network, you get a layer 2 frames, encapsulate it, and send it to the other side. Traffic between hosts is tunneled/encapsulated and invisible to the cloud. The tunneling method allows you to build whatever topology you want. You can even use the same on-premise IP and MAC addresses.

The first step is to export the VM from Vmware/KVM to Ravello networks. They have a tool that connects directly to vCenter so that you can suck information automatically. No changes were made, and it’s a simple drag-and-drop process. Conceptually, they extract the application environment, recreate it in their SaaS cloud, and then start a VM in the new environment.

Ravello parses the virtual machines’ metadata and automatically constructs the network and infrastructure. The application thinks it’s running in its native environment but in Ravello’s environment, which runs on top of either Amazon or Google.

Closing Points on Nested Hypervisors

In the ever-evolving world of virtualization, nested hypervisors are gaining significant attention. A nested hypervisor refers to the ability to run a hypervisor inside a virtual machine (VM). This innovative technology enables multiple layers of virtualization, providing increased flexibility and scalability for cloud environments and development testing.

Nested hypervisors offer numerous advantages, making them an attractive option for many organizations. One of the primary benefits is enhanced testing environments. Developers can create complex testing scenarios with multiple layers of VMs without needing multiple physical machines. This reduces hardware costs and allows for more efficient use of resources.

Additionally, nested virtualization improves scalability. Cloud service providers can offer more robust and scalable solutions by leveraging nested hypervisors, allowing clients to run their own hypervisors and manage their virtual environments independently.

Nested hypervisors are particularly beneficial for cloud service providers, software developers, and IT infrastructure teams. Cloud providers can offer nested virtualization as a service, enabling clients to deploy custom hypervisors and manage isolated environments. This is particularly useful for organizations that require specific configurations and control over their virtualized environments.

Software developers and IT teams benefit from nested hypervisors by being able to test and develop within isolated environments that mimic production settings. This capability allows for thorough testing, troubleshooting, and development of complex applications without affecting the main production environment.

While nested hypervisors offer numerous advantages, they also present certain challenges. Performance overhead is a potential concern as each layer of virtualization can introduce latency and resource consumption. Organizations must carefully consider resource allocation and ensure that their infrastructure can support the additional virtualization layers.

Security is another critical consideration. With multiple layers of virtualization, ensuring that each layer is secure and that there are no vulnerabilities that could be exploited is essential. Implementing robust security protocols and regular monitoring can mitigate these risks.