Saturday 6 February 2016

Azure Virtual Machines

In our last few blog post of Azure Series we discussed about Understanding Microsoft Azure,Virtual Networks and Azure Management Tools here we will be focussing on Azure Virtual Machines and will try and understand the various aspects related to it.

Azure Virtual Machines are virtual servers that runs in Azure cloud and make use of various Azure Services including Storage, Networks and Cloud services (Network Container).

For Virtual Machine to consume storage a Storage Account needs to be created for storing virtual hard disk files.

Azure Virtual Machines are provided as part of IaaS cloud offering and provides a public endpoint IP address.

VM's can communicate with other VM's which are part of the same Cloud Services and all the communication here is internal within the Azure and internet is not used for communication with each other.

With the Help of Built-in-Azure DNS Server name resolution of all the VM's which are part of the same Cloud Service is made available.

Again when it comes to Cloud Services there could be many VM's being part of same Cloud Service and in that case DNS (or IP address of Cloud Service) is not enough to communicate with a specific Virtual Machine.

This is something which can be achieved with Endpoints (Contains a Public Port which is publicly accessible over the internet and Private Port (RDP or HTTP) on which the service is running in Azure VM).

Endpoints are acting as helping hands in connecting Public Interface (VIP) on Cloud Service to Private Interface on a VM within the same Cloud Service.

When Creating a New Virtual Machine default endpoints are created automatically for Windows (RDP 3389, RemotePowerShell 5986) and Linux VM's (SSH 22).

Compute>Virtual Machine>Quick Create / From Gallery 

Select Image

Provide Name, Tier, Size, Username and Password

Create New or Select Existing Cloud Service, Cloud Service DNS Name, Region, Storage Account, Endpoints.

Additional Configuration and Security extensions can be also selected.

Even if we want to create additional endpoints for publishing other services like FTP,SMTP we can do so by defining the Protocol,Private and Public Ports to be used.

For Cloud Services to communicate with endpoints an IP address need to be assigned to cloud services which is done automatically by default or can be done manually by reserving an IP address.

When IP assignment is automatically done VIP (Virtual Internet Protocol Addresses) addresses are used which are acting as Public IP Address used to access Azure resources within that Cloud Service.

However when the IP's are specifically assigned to a Cloud Service Reserved Virtual Internet Protocol Addresses which will be associated with Cloud Services even when all the VM's are deleted or stopped are used.

Virtual Machines Sizing

Basic- Lower priced which doesn't include load balancing.

Standard- Provides resources for many workloads and auto-scaling,load balancing.

When it comes to Sizing Virtual Machines few points are of Key Importance like the Size of Virtual Machine is directly Proportional to its Pricing.

Virtual Machine Sizing can help you decide what would be the appropriate size for your virtual machines, also when it comes to hosting production workload A1 is considered as smallest size.

Virtual Machine IP Addressing

When Virtual Machines are created by default they are assigned a Virtual NIC (vNIC) with a Dynamic IP Address (DIP) which is randomly assigned by Azure from the range of available addresses for that Cloud Services, however if we want to choose specific IP range we can also make use of VNet's.

Static IP Address on VM's can also be assigned specially for those VM's which are running IP address sensitive applications and the static IP will be maintained for that VM even when the VM is Stopped.

For more information refer Microsoft Azure Essentials   

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