Virtualization
Tags: devops, cicd, docker, beginners
Published: 2024-04-15 04:24:00

Virtualization is a process that allows a computer to share its hardware resources with multiple digitally separated environments. Each virtualized environment runs within its allocated resources, such as memory, processing power, and storage.

## Before Virtualization: Overcoming Traditional Data Center Challenges

In the pre-virtualization era, managing data centers posed significant challenges, requiring extensive resources and investment. Let's delve into the intricacies of operating in this landscape:
1. **Data Center Space**: One of the foremost challenges was the physical space required to house servers and associated infrastructure. Traditional data centers demanded large footprints to accommodate racks upon racks of physical servers, resulting in significant real estate costs.
2. **Buying Physical Servers with Operating Systems**: Each application or service necessitated its dedicated server hardware, often leading to over-provisioning and under utilization of resources. Getting and setting up these physical servers with their own operating systems cost a lot of money upfront. It also needed careful planning to make sure they could handle the workload without any problems.
3. **Cooling System Integration for Heating Issues**: The heat generated by many servers working at the same time created a cooling problem. Cooling systems had to be meticulously designed and integrated to prevent overheating, ensuring optimal performance and longevity of hardware components. However, this added complexity and cost to the infrastructure setup.
4. **Cabling Cost and Implementation**: The intricate web of cables connecting servers, networking equipment, and storage devices not only added to the clutter but also introduced maintenance challenges. The cost of procuring, managing, and maintaining these cables further escalated the operational expenses.
5. **Maintenance Team**: Ensuring the seamless operation of physical servers required a dedicated team of IT professionals proficient in server maintenance, troubleshooting, and hardware replacement. This team was indispensable for addressing issues promptly and minimizing downtime.
6. **Electricity and Power Backup**: Power consumption was a significant concern, with servers consuming considerable amounts of electricity, leading to soaring utility bills. Moreover, ensuring uninterrupted power supply through backup generators or UPS systems was imperative to prevent data loss and maintain service availability during outages.
7. **Capex vs. Opex**: Procuring and maintaining physical server infrastructure incurred both capital expenditure (Capex) and ongoing operating expenditure (Opex). Capex encompassed the initial investment in hardware, while Opex included costs associated with power consumption, cooling, maintenance, and personnel salaries, making it a continuous financial burden.

## Benefits of Virtualization:

**Resource Utilization**: Virtualization allows for better utilization of physical server resources by running multiple virtual machines on a single physical host.
**Isolation**: Each virtual machine is isolated from other VMs on the same physical server, providing security and preventing interference between them.
**Flexibility and Scalability**: Virtual machines can be easily provisioned, moved, and scaled up or down as needed, providing flexibility in managing IT infrastructure.
**Disaster Recovery**: Virtualization facilitates the creation of backups and snapshots of virtual machines, making disaster recovery processes more efficient.
**VM snapshots**: A snapshot of a VM is a copy of that VM in that instant. You can take VM snapshots as backups, run the snapshots elsewhere, or restore them as needed. This is helpful before performing risky operations. If things go wrong, the previous version can be restored easily.
**VM migration**: You can move VMs from one host to another and resume their operations. For this, there are many uses. You can enable a fail over system where VM snapshots are backed up frequently to another host. If the primary host fails, the VM can switch over to the secondary host seamlessly.
**Cost Reduction**: Virtualization enables organizations to optimize resource usage, leading to cost savings. By consolidating multiple virtual machines onto fewer physical servers, businesses can reduce hardware costs, energy consumption, and space requirements. This consolidation also streamlines maintenance and management tasks, resulting in lower operational expenses over time.

## Hypervisor

Hypervisor is a software/firmware that creates and runs virtual machines.

**Firmware**: Firmware is software that provides basic machine instructions that allow the hardware to function and communicate with other software running on a device.
**Types of Hypervisor**:
Type 1 hypervisor/ Bare Metal Hypervisor/ Native Hypervisor
Type 2 hypervisor/ Hosted hypervisor

**Type 1 Hypervisor (Bare Metal)**: Runs directly on the host's hardware to control the hardware and to manage guest operating systems. Examples include VMware ESXi, Microsoft Hyper-V, and Xen.

**Type 2 Hypervisor (Hosted)**: Runs on top of a conventional operating system, allowing multiple operating systems to run concurrently on a single physical machine. Examples include VMware Workstation, VirtualBox, and Parallels Desktop.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ymclvmfnhu38hpj9nzfi.png)



## Benefits of Type-1 Hypervisor

Type-1 and Type-2 hypervisors are both used to virtualize hardware resources and run multiple operating systems on a single physical machine, but they have different architectures and offer distinct benefits. Here's an overview of the benefits of Type-1 hypervisors over Type-2 hypervisors:
**Performance**: Type-1 hypervisors generally offer better performance compared to Type-2 hypervisors because they run directly on the physical hardware without the need for an underlying host operating system. This direct access to hardware resources reduces overhead and improves efficiency.
**Resource Efficiency**: Type-1 hypervisors are lightweight and have a smaller footprint compared to Type-2 hypervisors, which require a full operating system to run. This results in better resource utilization and more efficient use of hardware resources.
**Security**: Type-1 hypervisors typically have a smaller attack surface compared to Type-2 hypervisors because they have fewer components and run closer to the hardware. This reduces the risk of security vulnerabilities and makes it harder for attackers to compromise the hypervisor.
**Isolation**: Type-1 hypervisors provide stronger isolation between virtual machines (VMs) because they run directly on the hardware and have full control over resource allocation. This ensures that VMs are more isolated from each other and prevents one VM from affecting others in case of a failure.
**Scalability**: Type-1 hypervisors are well-suited for large-scale virtualization deployments in data centers and cloud environments because they can manage multiple physical servers and VMs efficiently. They offer features like live migration and resource pooling to enable dynamic workload management and scalability.
**Reliability**: Type-1 hypervisors are designed for mission-critical applications and high availability environments. They often include features like fault tolerance, automatic fail over, and dynamic resource allocation to ensure reliable operation and minimize downtime.

Overall, Type-1 hypervisors are preferred for enterprise-level virtualization deployments where performance, security, scalability, and reliability are critical requirements. They offer better performance, efficiency, security, and isolation compared to Type-2 hypervisors, making them the choice for demanding virtualization environments.