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Gwyneth Peña-Siguenza
Gwyneth Peña-Siguenza

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AZ-303 Study Notes #2 Intro to VNET and VMs

Here is the second episode of my AZ-303 study notes series.

Video Notes

Virtual Networks

A VNET is an isolated container within Azure that provides network connectivity to resources.

Important components

  • Subnet: A VNET has one more more subnets. Resources that require network connectivity must reside in a subnet.

  • Address space: VNETs require one or more address spaces to provide private IP addresses to resources.

Important Considerations

  • Default connectivity: After creating a VNET, some connectivity is enabled by default. (Internet access, inter-subnet access).

  • Address range restrictions: Private IP address ranges are allowed. The smallest allowed is /29 and the largest is /8.

  • Reserved IP addresses: 5 IP addresses are reserved in each subnet. This includes the first 3 and last one. (x.x.x.0-3, x.x.x.255).

  • DNS and DHCP: Custom DNS can be configured for your VNET. DHCP is built-in and cannot be custom deployed.

  • Supported Protocols: VNETs support TCP, UDP, TCP/IP protocols.

  • Integrated Connectivity: VNETs are also built for various forms of integration. Including ExpressRoute, Private Link, VPN, and more.

  • Routing and Connectivity: NSG are more like a firewall, VNET routing is more about the actual pathway.

  • System Routes: Default routes configured by Azure to allow specific connectivity to work automatically.

  • Any subnet within a vnet will have outbound access to the internet.

  • Subnet to Subnet connectivity.

  • Custom Routes: User-defined routes which allow custom paths of communication to be enforced or blocked.

  • Route priority when you have multiple routes: Custom > BGP > System. The longest prefix match is always going to precedence first. a /32 will override a /24 when the other octets of the IP are matching.

Virtual Machines

A VM allows you to deploy virtualized Windows or Linux machines. They are helpful when you want to migrate existing compute workloads to the cloud and deploy advance compute solutions.

Key Components

  • Belongs to a resource group.
  • Created in a specific region.
  • Is configured with a given size that you can change also once it's created (requieres restart).
  • Built from an image of an OS.

Virtual Machine Sizes

The size of a VM influences several characteristics:

  • CPU resource allocation
  • Total available memory
  • Network Interface Card (NIC performance
  • Storage (Azure Disks) performance
  • Graphics capabilities
  • Influences limits (maximum NICs, disks)

Available sizes for your VM depend on Whether the virtual machine is running and the location of the virtual machine.

Thanks for tuning in.

I plan on creating more content around Azure; it's great to share what I've been learning.

If you have any feedback at all, please let me know in the comments below or reach out to me on socials.

Thanks for reading and possibly watching!

Discussion (1)

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Shaiju T

Hi 😄 Nice, AZ-303 is beta exam. Microsoft beta exams are offered at an 80% discount (code required). How can i receive this coupon code. Any idea ?