Tag Archives: Microsoft Azure

Azure Fundamentals Part 3 Summary

This is a summary of Azure Fundamentals part 3: Describe core solutions and management tools on Azure, one of the longer learning paths in the Azure Fundamentals series. The first of its seven modules is “Introduction to Azure fundamentals”, which is repeated in every learning path. The rest cover a number of different services spanning areas such as AI, source control and project management, observability, serverless, IoT, and different tools to interact with Azure.

This particular learning path uses a tedious format where each module discusses a couple of services, provides criteria to decide which to use, and then takes a while analysing those criteria for different use cases. This summary should save a lot of time if you’re preparing for the exam.

AI Services

This section is a summary of the Choose the best AI service for your needs module.

Approaches to AI:

  • Deep learning: based on neural networks. (The module doesn’t give this more than a brief mention.)
  • Machine learning: train a model and use it to make predictions.

AI services on Azure:

  • Azure Machine Learning: gives complete control to train a model using your own data. You can test it and then use it via a web API endpoint to make predictions.
  • Azure Cognitive Services: pre-built machine learning models covering:
    • Language: process natural language to identify meaning or sentiment
    • Speech: speech-to-text and text-to-speech, as well as translation and speaker recognition.
    • Vision: analyse pictures, videos and other visual content.
    • Decision: personalised recommendations (Azure Cognitive Services Personalizer), content moderation, and detection of anomalies in time-series data.
  • Azure Bot Service: used to develop chatbots. People can interact with these via text, interactive cards, and speech.

Source Control and Project Management

This section is a summary of the Choose the best tools to help organizations build better solutions module.

Azure DevOps Services is an offering similar to the Atlassian stack or GitHub, where you get Git repositories, task management, CI/CD, and more. Formerly known as (the dreaded) Team Foundation Server (TFS), this is now a SaaS product that includes:

  • Azure Repos: Git repositories
  • Azure Boards: task management, JIRA-style
  • Azure Pipelines: CI/CD
  • Azure Artifacts: hosts artifacts to be fed into later stages of a pipeline (e.g. testing or deployment)
  • Azure Test Plans: automated test tool that runs as part of a CI/CD pipeline

GitHub needs no introduction, but was acquired by Microsoft and so it can now be considered as an alternative to Azure DevOps. It remains popular for open-source projects with public repositories and communities built around them. GitHub Actions can be used to automate workflows, for example to implement CI/CD.

Compared to GitHub, Azure DevOps is more intended for enterprise development, and it has heavier project management and reporting tools as well as finer-grained access control.

Azure DevTest Labs is used to automate the provisioning and teardown of pre-configured environments (containing VMs or other resources) to test builds.

Observability

This section is a summary of the Choose the best monitoring service for visibility, insight, and outage mitigation module.

Azure Advisor provides recommendations to make best use of Azure and minimise costs, across the following categories:

  • Reliability
  • Security
  • Performance
  • Cost
  • Operational Excellence

Azure Monitor is use to ingest and analyse log and metric data from various sources. The data can also be used to trigger logic based on particular events. Application Insights is a service that collects telemetry from applications, and uses Azure Monitor under the hood.

Azure Service Health is a personalised view of Azure services, regions and resources that affect you. It helps you keep up to date with and find detailed information about:

  • Service issues
  • Planned maintenance
  • Health advisories (e.g. service retirements and breaking changes)

Working with Azure

This section is a summary of the Choose the best tools for managing and configuring your Azure environment module.

The Azure portal is a web-based user interface used to manage Azure resources. It is friendly for new users, but is not a good choice if you need to automate tasks.

The Azure mobile app supports iOS and Android, and is handy to manage Azure resources remotely when a computer is not available. You can use it to:

  • Monitor health and status of Azure resources
  • Check and fix issues
  • Restart a web app or VM
  • Run Azure CLI or Azure PowerShell commands

Azure PowerShell and the Azure CLI are both used to script interactions with Azure (or execute one-off tasks), via commands which call the Azure REST API underneath. Both provide the same automation benefits and are available for Windows, Linux, Mac, or within Azure Cloud Shell. The only difference is the syntax, where proficient Windows users might prefer Azure PowerShell, whereas the Azure CLI is based on Bash which is more familiar to Linux and Mac users.

ARM templates are a declarative way of describing the resources that need to be deployed using JSON. The ARM template is verified before execution, and creation of resources occurs in parallel while taking dependencies between them in consideration (i.e. they are created in the right order). If an error occurs, it’s easier to rollback everything than with shell scripts. ARM templates are a repeatable way to deploy entire environments.

Note: Azure PowerShell and Azure CLI scripts can trigger ARM templates, and vice versa.

Serverless

This section is a summary of the Choose the best Azure serverless technology for your business scenario module.

Azure Functions can execute a single function.

  • They run response to an event, such as a timer, HTTP request, or a new message on a queue.
  • They can be written in different programming languages including C#, Python, JavaScript, TypeScript, Java, and PowerShell.
  • They scale automatically.
  • They accrue charges only while they are running, based on number of executions and running time of each execution.
  • By default, they are stateless (they don’t normally keep state between executions).
  • Durable Functions are an extension allowing state to be preserved, and are used for more complex workflows involving multiple functions.
  • You just write the code and don’t manage any underlying infrastructure.

Azure Logic Apps:

  • Are a low-code/no-code service for automation and business integrations.
  • Are designed in a web-based designer.
  • Have triggers (events) that trigger actions (logic) via connectors.
  • Over 200 connectors are available to work with existing systems such as Salesforce, SAP, Oracle DB, etc.
  • You can also write your own connectors.
  • Billed based on number of executions and the type of connectors used.

Azure Functions and Azure Logic Apps can call each other.

Internet of Things (IoT)

This section is a summary of the Choose the best Azure IoT service for your application module.

IoT gathers data from devices in a backend system for processing and analysis. In this space, devices usually gather physical data via sensors, such as temperature or GPS. The devices can also be issued commands or have their firmware upgraded via an administrative portal.

Azure IoT Hub acts as a central message hub, allowing the backend IoT application and the devices to communicate in both directions. This includes command and control, where devices are controlled and issued commands directly. IoT Hub also tracks events such as device creation, failures and connections.

Azure IoT Central is another service providing a UI or dashboard on top of IoT Hub. It is a more complete solution and comes with starter templates to quickly get up and running, without writing any code (except for that which would run on the devices themselves).

Azure Sphere is an end-to-end IoT solution suitable for scenarios requiring the highest levels of security. This is based on three items:

  • The Azure Sphere micro-controller unit (MCU) which runs the operating system and processes signals from attached sensors.
  • A customised Linux OS that handles the security service and can run the vendor’s software.
  • Azure Sphere Security Service (AS3) ensures the security of the device by enforcing certificate-based authentication when the device connects to Azure, and checks for tampering. It also pushes any OS or other software updates to the device.

Devices based on Azure Sphere can talk to other Azure IoT services once they have been authenticated by AS3.

Azure Fundamentals Part 2 Summary

This is a summary of Azure Fundamentals part 2: Describe core Azure services. This learning path consists of five modules. The first one is the “Introduction to Azure fundamentals”, which is repeated in every Azure Fundamentals learning path — we’ve already covered this in Azure Fundamentals Part 1. The remaining four modules cover the core services: compute, storage (databases and unstructured data), and networking.

Database and Analytics Services

This section is a summary of the Explore Azure database and analytics services module.

Managed Database Services

Azure Cosmos DB:

  • is a globally distributed, multi-model database service
  • can scale throughput and storage across any number of Azure regions
  • provides fast, single-digit millisecond data access (latency)
  • stores schemaless data in atom-record-sequence (ARS) format
  • can be accessed using various different APIs including SQL, MongoDB, Cassandra, Tables, or Gremlin

Azure SQL Database:

  • is a relational database based on the latest stable version of MS SQL Server
  • is fully managed (PaaS) so things like upgrading patching, backups and monitoring are all taken care of
  • offers 99.99% availability

Azure SQL Managed Instance is also a managed SQL Server-based offering with 99.99% availability. However, this has better compatibility (i.e. feature coverage) with the SQL Server engine than Azure SQL Database (the example given is that Azure SQL Database supports only one default collation, which makes it a little hard to support foreign characters outside of the Latin set).

The Azure Database Migration Service provides guided migration from existing on-premises databases (e.g. SQL Server, MySQL, etc) to Azure-managed databases (e.g. Azure SQL Database). It works as follows:

  1. You first get an assessment report to identify any hurdles with migration.
  2. After any issues are resolved, the Database Migration Service carries out the migration for you.
  3. You just have to change the connection string in your applications.

Azure Database for MySQL:

  • is a managed version of MySQL based on MySQL Community Edition 5.6, 5.7 and 8.0
  • offers 99.99% availability
  • supports point-in-time restore as far back as 35 days
  • can scale as needed
  • can protect data in transit and at rest

Azure Database for PostgreSQL, similarly, is a managed PostgreSQL instance that offers high availability, can scale, and supports point-in-time restore up to 35 days. What’s interesting here is the deployment options:

  • Single server: 99.99% availability, can scale vertically
  • Hyperscale (Citus): horizontally scales queries across multiple machines using sharding; good for workloads of around 100GB or more

Big Data and Analytics

Azure Synapse Analytics is an enterprise data warehouse and big data analytics service. You can query data using either serverless or provisioned resources.

Azure HDInsight is a managed analytics service for enterprise based on open source software. It can process massive amounts of data and is suitable for things like ETL, data warehousing, machine learning and IoT. It supports different cluster types such as:

  • Apache Spark
  • Apache Hadoop
  • Apache Kafka
  • Apache HBase
  • Apache Storm
  • Machine Learning Services (R-based analytics)

Azure Databricks:

  • Analytics and AI based on Apache Spark
  • Supports languages: Python, Scala, R, Java, SQL
  • Supports libraries: TensorFlow, PyTorch, scikit-learn

Azure Data Lake Analytics is an on-demand analytics job service.

  • You set the dial for how much power you need
  • You pay for jobs only when they’re running
  • No hardware deployment

Compute Services

This section is a summary of the Explore Azure compute services module.

Virtual Machines

Azure virtual machines (VMs):

  • Include virtual processor, memory, storage and networking (IaaS)
  • Provide full control over the OS and applications, but you need to maintain them
  • Useful for lift-and-shift cloud migration

Azure virtual machine scale sets are a group of identical, load-balanced VMs that autoscale (increase/decrease in number) in response to demand or a defined schedule.

Azure Batch runs large-scale parallel and high-performance computing (HPC) batch jobs across a pool of VMs. It also identifies failures and requeues work.

Containers

Virtual machines provide an abstraction for CPU, memory and storage, making these easy to change. However:

  • You install the OS and applications (more maintenance effort)
  • They support only one OS at a time, which is not that great where different runtime environments are required
  • Starting up or taking snapshots can be slow

Containers provide a lighter-weight abstraction. Whereas VMs virtualise the hardware, containers virtualise the OS.

  • A container bundles a single app and its dependencies.
  • You deploy a containerised app to a container host.
  • The container host provides a standardised runtime environment which abstracts away the OS and infrastructure requirements.
  • The same container works in different environments (e.g. dev and prod).
  • Cluster orchestration can handle the problem of where to deploy containers, and take care of starting them, stopping them, and scaling them out.

Azure supports Docker, and provides the following services to manage containers:

  • Azure Container Instances: a PaaS service making it fast and easy to deploy containers without having to manage any VMs.
  • Azure Kubernetes Service: complete orchestration service suitable for distributed architectures with lots of containers

Hosted Apps

Azure App Service provides a managed environment for hosting different kinds of apps.

  • You pay depending on how much hardware is devoted to your host
  • Covers deployment, management, securing endpoints, scaling, and high availability (load balancing and traffic manager)

The following types of apps are supported:

  • Web apps: ASP .NET, ASP .NET Core, Java, Ruby, Node.js, PHP, Python, running on Windows or Linux.
  • API apps: REST APIs with HTTP or HTTPS endpoints, Swagger support, and the ability to publish to Azure Marketplace.
  • WebJobs: schedule/trigger a program (.exe, Java, PHP, Python, Node.js) or script (.cmd, .bat, PowerShell, Bash) in the same context as a web application – good for background tasks.
  • Mobile apps: backend for a mobile app, providing services such as databases, authentication via social logins, push notifications, or custom backend logic (C# or Node.js).

Serverless Functions

Azure provides Azure Functions and Azure Logic Apps, both serverless (i.e. they run on servers but they are hidden away) and triggering based on an event (e.g. timers, HTTP requests, queues, etc).

Azure Functions have the following features:

  • Automatic scaling
  • Micro-billing (you pay only for the time the code is running)
  • Stateless (restarted each time) or stateful (Durable Functions – context is passed to the function on execution)
  • Can run locally or in the cloud

Azure Logic Apps:

  • Execute workflows built on predefined logic blocks to automate business scenarios
  • Are created using a visual designer in the Azure Portal, or Visual Studio. They are stored as JSON using a defined schema.
  • Use connectors (over 200 in-built, or you can write your own) to interact with enterprise apps
  • Run only in the cloud (not locally)

Windows Virtual Desktop

Instead of shipping laptops to remote employees, IT administrators can use Windows Virtual Desktop to provide them with a cloud-based (virtualised) version of Windows.

  • They can remote in from Windows, Mac, iOS, Android or Linux
  • They can also access it directly from most modern browsers
  • It separates the compute environment from user devices, making it less likely for employees to leave confidential data on personal devices
  • Windows 10 Enterprise Multi-Session allows more than 2 users on the same VM
  • Uses reverse connect technology, so it does not open any ports for RDP

Azure Storage Services

This section is a summary of the Explore Azure Storage services module.

You can use several different data storage services after first creating an Azure Storage account.

  • The storage account will contain your data objects (e.g. blobs).
  • It also serves as a unique namespace for your data.
  • Data is secure, highly available, durable, massively scalable, and accessible over HTTP or HTTPS.

Azure Disk Storage is an IaaS service providing virtual disks for Azure VMs. Disks come in different sizes and performance levels (e.g. HDDs vs SSDs).

Azure Blob Storage:

  • Object (think “file”) storage solution for the cloud
  • Can store massive amounts of data
  • Data is unstructured, so you can put any type of data (e.g. videos, backups, etc)
  • Storage Account contains Containers (think “folders”), which in turn contain Blogs (think “files”)

Understanding Blob access tiers:

  • Hot access tier is for frequently accessed data.
  • Cool access tier is for infrequently accessed data stored for at least 30 days. Slightly lower availability and higher access costs are a tradeoff for lower storage costs.
  • Archive access tier is for rarely accessed data stored for at least 180 days, with flexible latency requirements. Data is stored offline, and this tier carries the highest costs to rehydrate and access data.
  • All access tiers can be set at the blob level, whereas only the hot or cool tier can be set at the account level.

Azure Files:

  • Fully managed file shares in the cloud
  • Accessible via Server Message Block and Network File System (preview) protocols
  • Can be mounted concurrently by cloud or on-premises deployments of Windows, Linux and macOS
  • Files can be accessed from anywhere using limited-time URLs using Shared Access Signature (SAS)

Networking

This section is a summary of the Explore Azure networking services module.

Virtual Networks

Azure virtual networks are an IaaS service providing cloud-based equivalents of networks in a data centre. Features include:

  • Isolation and segmentation – private IP address space, subnets
  • Internet communications – via public IP or load balancer
  • Communicate between Azure resources – virtual networks and service endpoints (which link Azure services to virtual networks)
  • Communicate with on-premises resources
    • Point-to-site VPN: computer connects to Azure virtual network
    • Site-to-site VPN: connect on-premises network to Azure network via VPN gateway
    • Azure ExpressRoute: dedicated private connectivity to Azure
  • Route network traffic – route tables, Border Gateway Protocol (BGP)
  • Filter network traffic – network security groups, network virtual appliances
  • Connect virtual networks – virtual network peering (connect networks even across regions)

VPN

VPN = virtual private network, a secure connection between 2 or more trusted private networks over an untrusted network (e.g. the internet).

Azure VPN Gateway:

  • Connects on-premises data centres to Azure virtual networks via site-to-site connection
  • Connects devices to virtual networks via point-to-site connection
  • Connects virtual networks to other virtual networks via network-to-network connection
  • You can deploy only one VPN gateway in each virtual network, but it can connect to multiple locations
  • Policy-based or Route-based: both use pre-shared key and rely on Internet Key Exchange (IKE) on v1 or v2 of IPSec

Policy-based VPN:

  • Supports IKE v1 only
  • Uses static routing: IP address configuration controls how traffic is encrypted/decrypted
  • Use this only where necessary (compatibility with legacy devices)

Route-based VPNs:

  • IPSec tunnels are modelled as a network interface
  • Support static or dynamic routing (using routing tables, BGP)
  • Are resilient to topology changes (e.g. creation of new subnets)
  • Support IKE v2
  • Use any-to-any (wildcard) traffic selectors

To deploy a VPN gateway you need the following in Azure:

  • A virtual network (address space must not overlap with the on-premises network)
  • A dedicated subnet for the VPN gateway
  • A public IP address (dynamic, but it won’t change until you delete the VPN gateway)
  • A local network gateway (represents the on-premises network from Azure’s point of view)
  • A virtual network gateway
  • One or more connection objects, connecting the on-premises VPN device’s IP address to the virtual network gateway’s IP address

To deploy a VPN gateway, you also need to have the following on-premises:

  • A VPN device supporting policy-based or route-based VPN gateways
  • A public-facing IPv4 address

VPN high availability scenarios:

  • Active/standby: 2 instances, brief downtime during maintenance
  • Active/active: additional tunnels and devices are used as fallback
  • ExpressRoute failover: use VPN gateways as fallback if ExpressRoute fails
  • Zone-redundant gateways: deploy VPN gateways or ExpressRoute across availability zones. Needs different gateway instances and Standard (not Basic) IP addresses.

ExpressRoute

Azure ExpressRoute:

  • On-premises data centre connects to Azure via a private connection (i.e. not over the internet) via a connectivity provider
  • It’s provides better speed, reliability, security, and more consistent latencies compared to going over the internet
  • It covers two layers of the OSI Model:
    • Layer 2: Data Link Layer (node-to-node communication on the same network)
    • Layer 3: Network Layer (addressing and routing on a multi-node network)
  • Provides connectivity to MS cloud services (e.g. Office 365, Dynamics 365 and Azure services)
  • ExpressRoute Global Reach: connect private data centres together via ExpressRoute
  • Uses BGP, dynamic routing

ExpressRoute connectivity models:

  • Colocation at cloud exchange: provider (e.g. ISP) provides Layer 2 and Layer 3 connections between your infrastructure and the MS cloud
  • Point-to-point Ethernet connection
  • Any-to-any networks: Layer 3 connection between your WAN and Azure

Azure Fundamentals Part 1 Summary

This is a summary of Azure Fundamentals part 1: Describe core Azure concepts. This learning path is made up of the following modules:

This is actually a bit of a mess. The first module is repeated in every Azure Fundamentals learning path. The second module is actually a repetition of the first, and the third covers part of the first module in more detail.

My goal here is to gather the most important points to serve as a decent summary for anyone preparing to take the Azure Fundamentals exam.

Cloud Computing

Cloud computing is the delivery of computing services over the internet.

  • You typically pay for what you use
  • Someone else manages certain resources for you (e.g. underlying physical hardware)
  • Compute power and storage are the main cloud resources
  • You can add/remove resources as needed

Basically, you’re renting computing and storage resources from someone else’s datacentre. Thus you don’t need to concern yourself with things like building security or cooling. The pay-as-you-go model is handy because you can provision (and de-provision) resources quickly and as needed:

  • No upfront costs
  • No need to buy and manage idle resources
  • Pay for additional resources when needed
  • Stop paying for resources when they are no longer needed

On a financial level, cloud usage shifts IT expense from CapEx to OpEx:

  • Capital expenditure (CapEx): up-front expenditure on infrastructure, which incurs depreciation over time
  • Operating expenditure (OpEx): pay for what you use, just like electricity

Advantages of cloud computing include:

  • High availability
  • Scalability (vertical and horizontal)
  • Elasticity (autoscaling)
  • Agility
  • Geo-distribution
  • Disaster recovery

Cloud Service Models

Azure and similar cloud providers offer a large range of services. These services abstract underlying resources at different levels, and are generally categorised as follows:

  • Infrastructure as a Service (IaaS): Azure manages the hardware, but you manage the OS, networking, etc. This category offers most control/flexibility but you have to take care of more things yourself (e.g. Azure virtual machines).
  • Platform as a Service (PaaS): Azure manages the hosting environment (e.g. VMs, networking). You just deploy your application (e.g. Azure App Service).
  • Software as a Service (SaaS): Azure manages all aspects of the application environment, including the application itself. You just bring your data (e.g. Office 365).

Serverless computing sits in the PaaS category, and offers a way to execute code in an event-driven manner that scales automatically, without needing to manage infrastructure. Servers are hidden (e.g. Azure Functions).

Public, Private and Hybrid Cloud

  • Public cloud: Azure sells services over the internet to anyone. Technically the physical server resources are shared.
  • Private cloud: Resources are dedicated to one organisation. This can be on-premises or hosted by the cloud service provider (i.e. Azure).
  • Hybrid cloud: Uses both public and private cloud, sharing some resources between them.

How Azure Works

  • Azure uses virtualisation
    • A hypervisor sits between hardware and OS
    • This allows a single physical server to run several VMs, at massive scale
  • Azure has datacentres all over the world
    • Each datacentre has many racks filled with servers
    • Each server includes a hypervisor to run multiple VMs
    • Servers are connected by network switches
  • One server in each rack includes a fabric controller
    • Fabric controller receives instructions from an orchestrator
    • Orchestrator manages everything that happens in Azure, including responding to user requests
  • API requests (e.g. to deploy a VM, from the Azure Portal) will go to an orchestrator, which talks to a fabric controller, which provisions/deprovisions resources as needed.

The above is explained graphically in a video at the What is Azure? page.

Miscellaneous

The Azure Portal is a web interface to view and manage your Azure subscription and resources. It has instances in every datacentre (so it’s close to users) and runs with high availability – updates incur no downtime.

The Azure Marketplace contains third party solutions to be run on Azure.

Azure Services

There is a long list of services on Azure, split up into a number of categories – you can see them at the Tour of Azure services. The more important of these are covered in subsequent learning paths, so let’s just take a high-level look at the categories at this stage:

  • Compute: VMs, container services, serverless functions, etc
  • Networking: virtual networking, load balancing, VPN, and other networking and security services
  • Storage: unstructured storage including blob, file (file server), queue and table (schemaless NoSQL) storage. These are all durable and highly available, secure, scalable, managed, and accessible via HTTP or HTTPS.
  • Mobile: backend services for mobile apps such as offline data sync, push notifications, connectivity to on-premises resources (e.g. SQL Server), and corporate sign-in.
  • Databases: several managed data store offerings ranging from managed RDBMSes (Azure SQL, MySQL, PostgreSQL, MariaDB), Redis, as well as CosmosDB (globally distributed NoSQL).
  • Web: App Service (managed hosting for web apps), Notification Hubs (push notifications), SignalR service, API management and more.
  • Internet of Things (IoT): connect, monitor and manage IoT devices.
  • Big Data: Synapse Analytics (managed enterprise data warehouse), HDInsight (Managed Hadoop clusters), Databricks (Apache Spark-based analytics service)
  • Artificial Intelligence (AI): Machine Learning Service (develop your own ML models) and Studio (use prebuilt ML algorithms). Cognitive Services are related, and comprise Vision, Speech, Knowledge Mapping, Bing Search, and Natural Language Processing.
  • DevOps: Azure DevOps (git repos, pipelines, testing, project management) and DevTest Labs (set up environments for testing).

Azure Subscriptions

An Azure account has one or more subscriptions.

  • Resources are anything you use within Azure (e.g. VMs)
  • Resource groups are a logical group of (related) resources
  • Subscriptions are a group of user accounts and resources; limits/quotas apply
  • Management groups are groups of subscriptions which inherit access, policy and compliance rules

Subscriptions can be used to separate things like environments (e.g. Dev and Prod), departments and billing. They can also be used to deal with limits at a subscription level by adding additional subscriptions. Subscriptions provide isolation in the form of a billing boundary (e.g. bill by department) and an access control boundary (e.g. you can only access Dev and Test environments).

A billing profile can be used to manage invoicing across subscriptions. A billing account can have multiple billing profiles (each of which is an invoice), each of which can have multiple invoice sections, each of which can contain multiple Azure subscriptions.

On management groups:

  • Can be nested to form a hierarchy; rules are inherited by children (other management groups, subscriptions, resource groups and resources)
  • Can give users access to multiple subscriptions via Role-Based Access (RBAC)
  • Can have up to 10,000 management groups in a single directory
  • Can have up to 6 levels of depth (excluding root and leaves (subscriptions))
  • Each can have only one parent
  • Each can have many children

On resource groups:

  • All resources must be in a resource group
  • Resource groups can’t be nested
  • Each resource can only be in one resource group
  • Serve as logical grouping of resources
  • Deleting a resource group deletes all the resources in it
  • Act as scope for RBAC permissions

The Azure Resource Manager (ARM) is a management layer that can be thought of as providing CRUD around resources. ARM also allows resources to be managed by templates – this is covered in more detail in a later learning path.

  • Azure Portal, Azure Powershell & Azure CLI (via SDKs), and REST clients talk to the Azure API
  • Azure API talks to ARM
  • ARM verifies authentication & authorisation
  • ARM can then perform actions (e.g. provision) on Azure services

Geography

A region is basically a geographical area where Azure has its datacentres.

  • A region has one or more datacentres nearby, connected by a low-latency network
  • Most resources have to be deployed to a region (which you choose)
  • Some services are only available in certain regions
  • Some services are global and don’t need a region at all
  • Deploying resources across regions gives you scalability, redundancy, data residency (when data must legally reside within a country), and allows data to be close to users

Some regions are special and not available to the general public. This includes several isolated datacentres used by the US Government, and datacentres in China which are operated by a partner.

Availability zones (AZs) are physically separate datacentres in an Azure region.

  • One or more datacentres with independent power, cooling and networking
  • Isolation boundary: it would take a major disaster for more than one AZ to fail in the same region (see also Region pairs further below)
  • AZs in the same region are connected via high-speed fiber-optic networks
  • Not all regions support AZs

Azure services supporting availability zones:

  • Are mainly VMs, managed disks, load balancers and SQL databases
  • Zonal services: pin resource to specific zone (e.g. VMs)
  • Zone-redundant services: replicates across zones

Region pairs:

  • A region is paired (directly connected) with another region in the same geography, at least 300 miles away (where available)
  • The pair is far enough that disasters shouldn’t take out both regions
  • Updates are rolled out to one region in a pair at a time
  • In case of outages to both regions, one region in a pair is prioritised to restore service quickly to at least one region in the pair
  • Data continues to reside within the same geography, which can be important for legal/compliance reasons

Azure Fundamentals Part 6 Summary

This is a summary of Azure Fundamentals part 6: Describe Azure cost management and service level agreements, both for my own exam revision and to help others get a more concise digest of the otherwise long-winded material.

Plan and Manage Costs

This part is a summary of the Plan and manage your Azure costs module.

Total Cost of Ownership

Total Cost of Ownership (TCO) refers to the total cost of running a data centre, which may include hidden costs such as software licences, electricity, network maintenance, salaries, etc.

There’s a TCO Calculator where you can compare running workloads on-premises vs on Azure (estimated). Here you:

  1. Define your workloads, i.e. select servers, databases, storage and networking.
  2. Adjust assumptions: here you can reuse existing licences via Software Assurance, decide whether you want to replicate storage across regions, and adjust other costs such as electricity, salaries and network maintenance.
  3. View report. Here you can adjust the timeframe between 1-5 years, and see a breakdown per category (e.g. compute or storage).

Azure Subscriptions

The different types of subscriptions are:

  • Free trial: 12 months of popular free services, credit against any service for 30 days, and more than 25 services always free. Services are disabled when the trial ends or the credit expires.
  • Pay as you go: pay for what you use. You can apply for volume discounts and prepaid invoicing.
  • Member offers: other subscriptions (e.g. Visual Studio) can provide discounts against Azure usage.

Purchasing Azure Services

You can purchase Azure services via:

  • Enterprise Agreement: commit to spending a certain amount over 3 years to get custom pricing.
  • Web Direct: use the Azure Portal directly; billed monthly.
  • Cloud Solution Provider: via a reseller (Microsoft partner).

Factors Affecting Cost

  • Resource type: different resources have different billing criteria
  • Usage meters: resources have billable units, e.g. VMs have CPU time and other units)
  • Resource usage: you can deallocate a VM to stop incurring charges, but you could still be charged for the disk if you leave it around
  • Subscription types (e.g. free trial)
  • Azure Marketplace: billing structures set by third party
  • Location: different regions have different prices
  • Bandwidth: network traffic in/out of Azure data centres is billed according to which geographical zone they’re in

Use the Azure Pricing calculator to estimate the cost of running a number of Azure services.

Manage and Minimise Costs

  • Understand estimated costs: use the TCO and Pricing calculators, and consult the docs about usage and billing for the relevant services
  • Monitor usage with Azure Advisor which provides suggestions (e.g. unused resources)
  • Use spending limits to restrict spending and avoid accidental overrun (there are also subscription limits and quotas from Azure)
  • Azure Reservations: prepay and get up to 72% discount over Pay as you go prices
  • Choose low-cost regions and locations (but keep in mind that you pay for network traffic between regions)
  • Research available cost-saving offers
  • Use Azure Cost Management + Billing to control spending (breakdown of costs)
  • Apply tags to identify cost owners (i.e. organise billing data, e.g. by department)
  • Resize underutilised VMs (need to turn them off, so consider downtime)
  • Deallocate VMs during off hours (e.g. dev/test running only during business hours) – can be scheduled
  • Delete unused resources
  • Migrate from IaaS from PaaS services
  • Save on licencing costs
    • Choose cost-effective OS (i.e. Linux)
    • Use Azure Hybrid Benefit to repurpose Windows Server or SQL Server software licences on Azure via Software Assurance

Service Lifecycle and Availability

This part is a summary of the Choose the right Azure services by examining SLAs and service lifecycle module.

Service Level Agreements

Service Level Agreements (SLA) define guarantees about the service provided by Azure, usually around availability/uptime.

  • Access SLAs from Service Level Agreements portal.
  • Uptime/downtime is measured as a percentage, e.g. 99.9% (or three 9’s) means the service can be down 0.1% of the time, which on a weekly basis works out to 10.1 minutes per week.
  • Downtime measurements are cumulative.
  • If the SLA is breached, you can claim a service credit which is a percentage of the fees you paid (defined in the SLA).
  • There’s generally no SLA for free services.
  • Azure status tells you when there’s an outage. From there you can also reach Azure Service Health, a personalised status view within the Azure Portal.
  • You get a composite SLA by multiplying the SLA for each service.
  • SLA is affected by customisations on resources (e.g. tier, or disk type) as well as redundancy (e.g. VMs behind a load balancer).

Azure Service Lifecycle

New services go through the following stages:

  1. Development
  2. Public preview
  3. General availability

Things in preview include:

  • Preview (new) services
  • Preview features for existing services
  • Preview features for Azure Portal

Use the Azure updates page to keep track of the lifecycle status of features/services.