Azure Compute Resources Flashcards
Virtual Machine Extensions
Small applications that provide post-deployment config and automation tasks on Azure VMs.
(e.g., software installation, anti-virus protection, configuration script inside)
Naming VMs
A good convention is to include environment, location, instance, product/service, role.
(e. g., devusc-webvm01) dev environment, located in US south central, for web dev
(e. g., prodausse-sql03) prod in Australia south east, for sql, 3rd instance.
VMs - Compute costs
Priced per hour
Charged per minute
Stopping and deallocating a VM releases the hardware and incurs no cost
VMs - Compute costs
Priced per hour
Charged per minute
Stopping and deallocating a VM releases the hardware and incurs no cost
VM Storage costs
Charged for the storage a VM uses.
Status of VM has no relation to storage charges (i.e., a stopped/deallocated VM still incurs storage costs)
VMs disks
All Azure VMs have at least two disks.
OS disk (C:\) Temp disk (D:\) Can have one or mare data disks
Connecting to virtual machines - windows os
Remote Desktop Protocol (RDP) - establish a GUI
Windows Remote Management (WinRM) - establish a command line session to an Azure VM that runs any supported version of windows.
connecting to virtual machines (linux)
SSH is an encrypted connection protocol that allows secure sign-ins over unsecured connections. SSH is the default connection protocol for Linux VMs hosted in Azure.
VMs : Update Domain
An update domain (UD) is a group of nodes that are upgraded together during the process of a service upgrade (rollout).
VMs: Fault Domain
A fault domain (FD) is a group of nodes that represent a physical unit of failure. A fault domain defines a group of virtual machines that share a common set of hardware, switches, that share a single point of failure.
Availability Zones: Zonal Services
Pins the resource to a specific zone (for example, virtual machines, managed disks, Standard IP addresses).
Availability Zones: Zone-redundant services.
Platform replicates automatically across zones (for example, zone-redundant storage, SQL Database).
VM extensions
Azure virtual machine extensions are small applications that provide post-deployment configuration and automation tasks on Azure VMs.
(e.g., if a virtual machine requires software installation, anti-virus protection, or a configuration script inside, a VM extension can be used)
Custom Script Extensions (CSE)
used to automatically launch and execute virtual machine customization tasks post configuration.
Your script extension may perform simple tasks such as stopping the virtual machine or installing a software component. However, the script could be more complex and perform a series of tasks.
Desired State Configuration (DSC)
is a management platform in Windows PowerShell. DSC enables deploying and managing configuration data for software services and managing the environment in which these services run.
Web App Scaling: Scale Up
You scale up by changing the pricing tier of the App Service plan that your app belongs to.
Get more CPU, memory, disk space, and extra features like dedicated virtual machines (VMs), custom domains and certificates, staging slots, autoscaling, and more.
Web App Scaling : Scale Out
Increase the number of VM instances that run your app. You can scale out to as many as 30 instances, depending on your pricing tier.
The scale instance count can be configured manually or automatically (autoscale). Autoscale is based on predefined rules and schedules.
App Service Plan Scaling: Metric-Based
Metric-based rules measure application load and add or remove VMs based on that load.
For example, do this action when CPU usage is above 50%. Examples of metrics are CPU time, Average response time, and Requests.
App Service Plan Scaling: Time-based.
Time-based (schedule-based) rules allow you to scale when you see time patterns in your load and want to scale before a possible load increase or decrease occurs.
For example, trigger a webhook every 8am on Saturday in a given time zone.
Creating an App Service: config choices
Requires a resource group and service plan.
Name: Must be unique Publish: Host code or a docker container Runtime stack: The stack to run the app (language, SDK) Operating System: Linux or Windows Region: ...
App Service: Deployment Slots
Deployment slots are live apps with their own hostnames. App content and configurations elements can be swapped between two deployment slots, including the production slot.
App Service: Application Insights
A feature of Azure Monitor that monitors your live applications.
(request rates, response times, failure rates, dependency rates, page views, load counts, user and session counts, performance counters)
Containers vs VMs: Isolation
Container: lightweight isolation from the host and other containers
VMs: Complete isolation from the host OS and other VMs (strong security boundary)
Containers vs VMs: OS
Containers: Runs the user mode portion of an operating system and can be tailored to contain just the needed services for your app.
VMs: Runs a complete operating system including the kernel, thus requiring more system resources (CPU, memory, and storage).