Azure Virtual Machines Concepts

Azure Virtual Machines (VMs) provide on-demand, scalable computing resources. VMs are a part of Azure's Infrastructure as a Service (IaaS) offering, allowing you to deploy and manage infrastructure without having to buy and maintain the physical hardware.

Core Concepts

Virtual Machine Components

An Azure VM is made up of several components:

• Operating System Disk: This is a managed disk that contains the operating system and its files. It's essential for booting up the VM.
• Data Disks: These are managed disks that you attach to the VM to store application data. You can attach multiple data disks to a VM.
• Network Interface (NIC): This enables the VM to communicate with other VMs and the internet. Each VM must have at least one NIC.
• Virtual Network (VNet): VMs are connected to an Azure Virtual Network, which provides a private network in the cloud.
• Public IP Address (Optional): If you need to access the VM from the internet, you can assign a public IP address.

VM Sizes and Series

Azure offers a wide variety of VM sizes, categorized into different series. Each series is optimized for specific workloads:

• General Purpose (e.g., D-series, B-series): Balanced CPU-to-memory ratio, suitable for most workloads like web servers, small-to-medium databases.
• Compute Optimized (e.g., F-series): High CPU-to-memory ratio, ideal for compute-intensive applications, batch processing, and web servers.
• Memory Optimized (e.g., E-series, G-series): High memory-to-CPU ratio, suitable for in-memory applications, large relational databases, and big data analytics.
• Storage Optimized (e.g., L-series): High disk throughput and IOPS, designed for big data, SQL, and NoSQL databases.
• GPU Optimized (e.g., N-series): For graphics-intensive workloads, AI, and machine learning.

Managed Disks

Azure Managed Disks are the recommended way to manage storage for VMs. They abstract away the underlying storage and handle availability, durability, and performance. Key types include:

• Standard HDD: Cost-effective for development/test environments or less I/O-intensive workloads.
• Standard SSD: Consistent performance for low-latency workloads.
• Premium SSD: High-performance, low-latency SSDs for mission-critical workloads.
• Ultra Disk: Highest performance for I/O-intensive workloads like top-tier databases.

Availability and Scalability

Azure VMs can be deployed in ways that ensure high availability and scalability:

• Availability Sets: Distribute VMs across different fault domains and update domains within a datacenter to protect against hardware failures and planned maintenance.
• Availability Zones: Replicate VMs across physically separate datacenters within an Azure region, providing protection against datacenter-level failures.
• Virtual Machine Scale Sets (VMSS): Allow you to deploy and manage a set of identical, load-balanced VMs. You can automatically scale the number of VMs in response to demand.

Key Operations

Creating a VM

VMs can be created using the Azure portal, Azure CLI, Azure PowerShell, or ARM templates.

az vm create --resource-group MyResourceGroup --name MyVM --image Ubuntu2204 --admin-username azureuser --generate-ssh-keys

Connecting to a VM

For Windows VMs, you use Remote Desktop Protocol (RDP). For Linux VMs, you typically use SSH.

ssh azureuser@your_vm_public_ip

Managing VM State

You can start, stop, restart, and deallocate VMs. Stopping a VM releases compute resources, while deallocating it also releases IP addresses.

Common Use Cases

• Hosting web applications and APIs
• Running development and testing environments
• Deploying enterprise applications like SAP or Oracle
• Big data analytics and high-performance computing
• Disaster recovery solutions

Explore the Azure documentation further to dive deeper into specific VM features and configurations.