Azure Virtual Machines

Azure Virtual Machines (VMs) empower you to effortlessly create and utilize VMs in the cloud. These VMs offer Infrastructure as a Service (IaaS) by providing a virtualized server, enabling their versatile usage. Similar to a physical computer, you have the freedom to personalize all the software running on your VM. VMs are the perfect choice when you require:

• Complete control over the operating system (OS).
• The ability to run customized software.
• Custom hosting configurations.

By utilizing Azure VMs, you gain the flexibility of virtualization without the need to invest in and maintain physical hardware that supports the VM. However, as an IaaS offering, it is still necessary to configure, update, and maintain the software running on the VM.

Furthermore, you can swiftly provision VMs by creating new instances or utilizing preconfigured VM images. These images act as templates for VM creation, potentially including an OS and other softwares like development tools or web hosting environments.

Scaling VMs in Azure allows you to run individual VMs for testing, development, or minor tasks. Alternatively, you can group VMs together to achieve high availability, scalability, and redundancy. Azure simplifies VM grouping through features such as scale sets and availability sets.

Virtual Machine Scale Sets enable you to create and manage a group of identical, load-balanced VMs. Instead of manually ensuring identical configurations for multiple VMs and setting up network routing parameters, scale sets automate most of this work. They allow centralized management, configuration, and updates for a large number of VMs within minutes. VM instances can automatically scale up or down based on demand or a defined schedule. Scale sets also deploy a load balancer to ensure optimal resource utilization. They enable the creation of large-scale services for computing, big data, and container workloads.

Virtual Machine Availability Sets are another tool that enhances resilience and availability. Availability sets ensure VMs have staggered updates and diverse power and network connectivity, preventing a complete loss of VMs due to a single network or power failure. Availability sets group VMs based on update domains and fault domains.

1. Update domains group VMs that can be rebooted simultaneously, allowing updates to be applied while ensuring only one update domain is offline at a time. An update group has a 30-minute recovery time before the next update domain's maintenance begins.
2. Fault domains group VMs based on common power source and network switch, with up to three fault domains by default. Distributing VMs across fault domains safeguards against physical power or networking failures by connecting VMs to different resources.

Configuring an availability set incurs no additional cost; you only pay for the VM instances you create.

There are various scenarios where VMs are commonly utilized, including:

1. Testing and development: VMs provide an efficient way to create different OS and application configurations, easily removable when no longer needed.
2. Running applications in the cloud: Certain applications benefit from the cost savings and flexibility of running in the public cloud. VMs allow scaling resources as needed, optimizing expenses.
3. Extending your datacenter to the cloud: By creating a virtual network in Azure and adding VMs to it, organizations can expand their on-premises network capabilities. This approach offers deployment advantages and cost savings compared to a solely on-premises environment.
4. Disaster recovery: VMs can be employed for cost-effective disaster recovery. In the event of a primary datacenter failure, critical applications can run on Azure VMs until the primary datacenter is operational again.
5. Cloud migration (lift and shift): VMs are an excellent choice when transitioning from physical servers to the cloud. You can create VMs with minimal changes by hosting images of the physical servers. However, it remains your responsibility to maintain the VM by managing the installed OS and software.

When provisioning a VM, you have the opportunity to select associated resources, including:

1. Size (purpose, number of processor cores, and RAM capacity).
2. Storage disks (hard disk drives, solid-state drives, etc.).
3. Networking (virtual network, public IP address, and port configuration).