AZ-104 - Compute

https://learn.microsoft.com/en-us/training/paths/az-104-manage-compute-resources/

What is an Azure virtual machine? Name five things Azure provides tools to assist with when managing VMs

An IaaS compute resource where you have complete control over it’s configuration. Azure also provides tools for scaling, backup, monitoring, securing and patching OS

Name six components that are created when creating a virtual machine

Virtual Machine, Disks, Virtual Network, Network Interface Card (NIC), Network Security Group (NSG), IP addresses (pubilc and/or private)

When creating a VM if a VNet is not provided what happens?

Azure automatically creates the VNet for the VM

Which disks are automatically created when creating a VM?

The Operating System (OS) and Temp disks

When configuring a VM what four properties do you need to provide?

VM name, Location, VM Size + OS Image

What is the maximum possible length for a VM name

64 characters long on Linux and 15 characters on Windows

Is it possible to change a VM name while it is running?

No. The VM needs to be redeployed to change it’s name

Name the six VM size families

General Purpose, Compute Optimized, Memory Optimized, Storage Optimized, GPU, High Performance Compute

What is the resource profile of compute and memory optimized VMs?

Compute optimized VMs have a high CPU to memory ratio and memory optimized VMs have a high memory to CPU ratio

What is the resource profile and use case for storage optimized VMs?

Storage optimized VMs have high disk throughput and I/O. These are good for hosting databases

Which VM size has optional high throughput network interfaces?

High Performance Computing

What are the use cases for GPU VMs?

Graphics or model training

Name three use cases for memory optimized VMs

Relational DBs, caches, in memory analytics

Which VM size is best for medium traffic web servers, batch processing and app servers

Compute optimized

Which VM family is best for test/dev environment

General Purpose

What two parts are there to VM costs?

Compute costs and storage costs

How are compute costs calculated?

Compute costs are billed per minute of use (not if the resource is stopped or deallocated) and depend VM size, location and Operating System

For a VM what cost is still charged even if the VM is stopped or deallocated?

Storage costs

What are VM reserved instances?

By reserving a VM for one or three years you can save money on the cost of the VM. If you cancel early you may inccur an early cancellation fee.

What time options are there for reserving a VM?

One year or three year reservation

Name the five disk types for Virtual Hard Disks (VHD)

Standard HDD, Standard SSD, Premium SSD, Premium SSD v2, Ultra Disk

Which VHD types can be used as the OS disk for a VM?

Standard HDD, Standard SSD, Premium SSD (not Premium SSD v2 or Ultra Disks)

What is the max disk size for the five VHD types?

Standard HDD: 32TB, Standard SSD: 32TB, Premium SSD: 32TB, Premium SSD v2: 65TB, Ultra: 65TB (Disks that can host OS are 32TB, Disks that cannot are 65TB)

What is the max throughput (MB/s) of the five VHD types

Standard HDD: 500, Standard SSD: 750, Premium SSD: 900, Premium SSD v2: 1200, Ultra: 4000

What is the max IOPS of the five VHD types

Standard HDD: 2,000, Standard SSD: 6,000, Premium SSD: 20,000, Premium SSD v2: 80,000, Ultra: 160,000

Name the use cases for Standard HDD VHDs

Backup, non-critical or infrequently accessed VMs

Name the use cases for Standard SSD VHDs

web servers, light use enterprise systems, dev/test environments

Name the use cases for Premium SSD VHDs

Production and performance sensitive workloads

Name the use cases for Premium SSD v2 VHDs

Production and performance sensitive workloads with low latency and high IOPS

Name the use cases for Ultra VHDs

IO intensive workloads such as SAP HANA, DBs and transaction heavy workloads

Name the seven methods for creating a VM

ARM templates, Terraform, Azure CLI, PowerShell, REST API, Client SDK and Azure Automation Services

What command is used to create a VM from Azure CLI?

az vm create

What command is used to create a VM from PowerShell?

New-AzVm

What is Azure automation services? Name the three components that make this up

Automation services consists of three tools that help with management of VMs. This includes process automation, configuration management and update management.

What is Azure process automation?

A tool in Azure Automation Services that lets you automate repeatable tasks to help manage VMs. This reduces human error and improves response times

What is Azure configuration management?

An Azure Automation Services tool that automatically manages Operating System (OS) updates for VMs

What is Azure update management?

An Azure Automation Services tool that automatically manages VM updates

What is Azure auto shutdown?

This allows you to configure a schedule for automatically scaling down and turning on VMs to save costs when not needed

What is Azure backup for VMs?

A service that allows you to backup VMs running in the cloud or on prem to the cloud

What are availability sets?

This is a logical grouping of VMs spread across fault and update domains to reduce the chance a correlated failure or update takes all the VMs offline at the same time. All VMs in an availability set should be identical.

What are update domains?

Update domains are a feature of availability sets where VMs in the same update domain can be updated at the same time without taking the entire availability set offline. When an update is performed it is done on one update domain at a time. By default there are five update domains in an availability set but up to twenty can be configured.

What are the default and maximum numbers of update domains in an availability set?

By default there are five and the maximum is twenty

What are fault domains?

Fault domains define a group of VMs that share the same power source and network switch. These are used in availability sets so if a hardware failure occurs (switch or power failure) the entire availability set isn’t taken offline. By default there are two fault domains but three can be configured.

What are virtual machine scale sets?

VMSSs allow you to deploy, manage and autoscale a set of identical VMs

How many VMs can be in a virtual machine scale set?

VMSS can hold up to 1,000 VMs if using an off the shelf image and 600 if using a custom image

What five options do you need to configure when setting up a virtual machine scale set?

Orchestration mode (uniform or flex), VM architecture, VM size/SKU, VM image, spreading algorithm (advanced option)

What types of autoscaling rules can be used with virtual machine scale sets?

When a CPU threshold is hit or on a schedule

Why might you want to setup schedule autoscaling rules?

To scale up in antcipation of demand at specific times (e.g. black friday)

What is an app service plan

Defines the compute resources (VMs) app services are run on

Name the nine app service plan pricing tiers

Free, Shard, Basic, Standard, Prev1/v2/v3, Isolated v1/v2

What are the three app service plan isolation tiers? What are the differences?

Shared where VMs are shared between customers, Dedicated where a VM is dedicated to each app service plan and Isolated where a VM and VNet are dedicated to each app service plan.

What app service plan tiers have the shared isolation tier

Free and Shared

What app service plan tiers have the dedicated isolation tier

Basic, Standard, Premium v1/v2/v3

What app service plan tiers have the isolated isolation tier

Isolated v1/v2

What autoscaling options are available for app service plans?

Autoscaling rules can be setup on any Azure metric or a schedule

What app service plan tiers can have autoscaling?

All except free and shared (Basic, Standard, Premium v1/v2/v3, Isolated v1/v2

What is an app service

A Platform as a Service (PaaS) offering that allows deployment and scaling of applications without needing to manage the underlying infrastructure

What six configuration setting are required when creating a VM (not post creation settings)

Name, Publish (Code or Docker image), Runtime stack, Operating System, Region, Pricing plan (for App Service Plan)

What three post creation app setting may you need to set for an app service?

Always on (needed for CRON jobs), HTTPS only and session affinity

What type of job do you need to enable ‘always on’ in app setting to run on an app service?

To allow CRON jobs to execute

What is CI/CD?

Continuous Integration/Continuous Deployment

What five out of the box CI/CD options are there for app services

Azure DevOps, Github, bitbucket, FTP and local git repo

What manual deployment options are available for app services

remote git, one drive or dropbox

What are deployment slots? What are two advantages of using deployment slots?

These are secondary web apps that new versions of an app can be deployed into, warmed up and tested before being swapped into the main slot. This means there is no downtime and it is easy to swap back to the old version if there is an issue

What app service plan tiers are deployment slots available for?

Standard, Premium (v1/v2/v3) and Isolated (v1/v2)

Describe app service security

App services have built in authentication and authorization. The module runs in the same environment but separately and is configured using app setting. When enabled every incoming HTTP request goes through the module

How do you setup custom domains for an app service?

1. Reserve the domain name either in Azure or through a third party

2. Create DNS records to map the domain. This can either be an A or CNAME record

3. Enable the custom domain by adding it to the web app

Describe app service backups

App service backups make a backup of an app service to a storage account container in the same subscription. Backups can be max 10GB and partial backups are possible to exclude static or large files. Backups consist of a zip file and xml manifest which contains a list of the contents of the zip file. Backups are only available standard, premium and isolated app service plans.

What is the maximum size possible for an app service backup?

10GB

What app service plans are app service backups available to?

Standard, Premium (v1/v2/v3), Isolated (v1/v2)

What restrictions on containers are there for app service backups?

They must be in the same subscription

What files make up an app service backup?

A zip file and an xml manifest containing a list of the contents

What is an Azure Container Instance?

Allows you to run docker images in Azure. This is a Container as a Service offering that means you don’t have to worry about underlying infrastructure (as with IaaS VMs) but have control over the environment (unlike with PaaS app services)

What is the difference in security between Azure Container Instances and Virtual Machines?

Azure Container Instances have weak security boundaries (which is more lightweight) and Virtual Machines have strong security boundaries

What is the difference in the OS run on Container Instances and Virtual Machines?

Containers only run the user mode portion of the OS (more lightweight) and the VM runs the whole OS

What tools are used to deploy both single and multiple containers?

Single containers are deployed by Docker via command line. Multiple containers can be deployed by an orchestrator such as Azure Kubernetes Service

What tools are used to deploy both single and multiple VMs?

Single VMs can be deployed using Hyper-V or Windows Admin Center. Multiple VMs can be deployed by PowerShell or a VM manager

What persistent storage does Azure Container Instances use?

Disks for local and Files SMB for shared

What persistent storage do Azure Virtual Machines use?

Disks for local and Files SMB for shared

What are Azure container groups?

A collection of containers that run on the same host machine. This means they share a lifecycle, resources, local network and storage. This can be useful for services that are separate (different language or managed by different team) but need to be on the same resources.

What are some use cases for Azure container groups?

This can be useful for services that are separate (different language or managed by different team) but need to be on the same resources. This includes logging services, configuration services or extending legacy applications

What are Azure Container Apps?

A serverless platform that allows you to run containerized applications without worrying about server config, deployment or container orchestration

What is Azure Kubernetes Service?

A managed Kubernetes service that allows you to deploy and manage containerized applications