Top 10 Azure Glossary: Demystified
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1. Affinity Group
“Affinity group” AKA Scale units helps co-locating related resources in close proximity to reduce network latency. for e.g., when you launch a multi-tiered web application with front end tier, business logic tier and database server, you don’t want to place these resources in different parts of the datacenter instead you want to group it together for better network performance. Azure highly recommends Affinity Group for grouping of related resources but doesn’t mandate.
Azure Data centers consists of multiple Affinity groups and not all the affinity groups contains all the Services of Azure, for e.g. New High power VM Families, Internal Load Balancers, Reserved IPs may not be available in all the Affinity Groups.
2. Regional VNet
Regional VNet is the enhanced version of VNet. Until 2014, VNet was originally bound to Affinity Groups which is just a sub section of Azure Data Center. Affinity group has limited set of resources and it doesn’t contain all the services offered within a region. As of this writing, Azure has 17 regions spread globally and planning to power up many more datacenters. When you create a Regional Virtual Network, it can span the entire region and thus you can avail all the services available within the region and not limited to Affinity Groups.
3. Availability Set
Azure’s main promise is High Availability. To achieve HA for your applications, it is always recommended to run at least two instances of your solution to qualify for HA and 99.95 Azure SLA.
- Availability Set has two main concepts called
- Fault Domain & Upgrade Domain.
- As the name suggest
- Fault Domain
is an individual or group of Container/Rack placed inside the Azure Datacenter that shares Power and Network Switches. 2 Virtual Machines placed under an Availability group, will be virtually deployed in two different Fault Domains so that problems occurred in one Fault domain will not affect another.
Upgrade Domains is a categorization of resources to manage Host Operating Updates and patches. This helps us with avoiding both the VMs get updated or patched at the same time.
4. Resource Group
Resource Group helps you to group all the related services together for better resource management, tagging and billing. Not to be confused with Affinity Groups, which is keeping virtual resources close proximity.
For e.g. If you manage 2 different projects 1. Internal SharePoint Portal, 2. Public facing corporate website built on PHP. Each of this solution have different set of resources and hence you may want to group them together.
Key pointers about Resource Group at this moment are
- Default and Maximum Resource group that you can create within a subscription is 500.
- Resource Group should not be confused with Active Directory Group functionally, both are two different services.
- Linking of shared resources between groups is not fully functional yet
- Resource Group can span regions.
Be default VMs launched within Virtual Networks can communicate to each using their private address, but if you want to make VMs placed in different Networks irrespective of whether it is within azure/on premise/other cloud, you need public IPs otherwise called as Endpoints. When you create VMs, ports like Remote Desktop, Windows PowerShell Remoting, and Secure Shell (SSH) are automatically opened, but you can also open other ports like FTP, SMTP, DNS, HTTP, POP3, IMAP, LDAP, HTTPS, SMTPS, IMAPS, POP3S, MSSQL, and MySQL as it requires.
Each endpoint in the VM has two ports i.e. Public Port & Private Port. Public port is used for incoming traffic from the internet and private port is for internal communication with other services within the virtual network.
6. Public Virtual IP Address/Dynamic IP Address
When you first create a Cloud Service in Azure you will be assigned with Virtual Public IP Address. This VIP will not be released until all the VMs placed inside the Cloud services is successfully Deleted or Stopped (De-allocated).
Dynamic IP Address (DIP) are nothing Private IP address allocated by DHCP (Dynamic Host Control protocol), also note that it bounds to the VNet CIDR block defined by the user. Similar to the Public IP, DIPs are also not release until all the VMs placed inside the Cloud services is successfully Deleted or Stopped (De-allocated).
Reserved Virtual IP Address
Users can reserve IP addresses for their subscription. This helps them with predictable IP address that can associated with their Cloud Services and Virtual Machines. By default when you delete or stop (De-allocate) your instances the VIPs will be released to Azure IP address pool, but when you reserve IPs it will remain in your subscription until to remove Reserved IPs from your subscription.
7. Instance Level Public IP Address
Instance level IP address is associated directly to the Virtual Machine Instances rather than to the Cloud Services where you back all the Virtual Machines within. Currently you can only allocate one PIP to a VM instance and it is not currently supported Multi NIC VMs.
Instance Level IP addresses can be used when you simply want to connect your VM with an IP instead of using Cloud Service endpoints opened individually for each ports like
Other benefits includes receiving traffic on any port instead of selective ports which is best suitable Passive FTP where the selection of the ports are completely dynamic in nature, similarly outbound traffic from VM can be routed via PIP.
At this moment, requesting of Instance level IPs as well as allocation if IPs can only be done using Windows PowerShell and Rest APIs.
8. X-PLAT CLI
9. Cloud Service
Out of all the Naming Conventions of Microsoft Azure, Cloud Service is the single most confusing and ubiquitous term. Cloud Service is a very broad term and used by everyone, everywhere basically for one reason, anything hosted out of premise is generally called as Cloud Service.
Cloud Service in Azure is nothing but a DNS name e.g. http://<<contonso>>.cloudapp.net or http://<<contonso>>.azure websites.net which could be mapped with a custom domain. Creating cloud service is the first step of creating public interfaces like WebApp, Mobile services or Azure VM.
10. App Services
Azure App Service is the new term coined by Microsoft recently which consolidates Websites (Web Roles/Worker Roles), Web Jobs, Mobile Services, API Services together and offers it as a package. As of writing this article, it’s currently available only in the preview portal. There was lot of confusions within the Developer community as when to choose Web Roles, Website, Mobile Services etc because of close resemblance to each other. In fact you can create a mobile services using Worker Role or a Web role.
Now let’s look at what these individual services can do
This is nothing but Azure Websites that helps developers to quickly build websites using variety of different programming languages and host and scale seamlessly using Azure PaaS offering.
It’s a new breed of service targeted at developers and technical business users to orchestrate and create API workflows. APIs found everywhere, almost all the services exposes APIs. Logic Apps helps you to connect various APIs together in a secured and organized manner. Logic App provides out of box Social Media connectors for Twitter, Facebook, Yammer. Enterprise Connectors for SAP, Marketo, Salesforce and Azure Data Service connectors for Sharepont, Mobile Services, Storage etc. If you don’t find connectors of your favorite services, you can build one by yourself using API App service.
It’s an API hosting Service where you can build APIs using various programming languages including C#,Java, Python,Node.js,PHP and host it with Azure Apps service. API App connects seamlessly with Azure Web App/Mobile and Logic App. The 2 major benefits of API app are 1. Simplification of Security using AD/SSO and OAuth and 2. Quick API deployments and automated versioning support.
About the Author
Ilyas is a Cloud Solution Architect at 8K Miles specializing Microsoft Azure and AWS Clouds. He is also passionated about Big Data, Analytics and Machine Learning Technologies.