Azure Architect Expert Study Notes
The following is a quick and dirty list I made for the Architect exams so that I could read them quickly before the exam itself. This is mostly for the AZ-302 but good to know regardless of what exam your doing.
- Blob Storage is NOT for storing Virtual machine vhd files, blob storage is for block blobs and append blobs and not page blobs)
- You can use Traffic Manager to sit above 2 virtual machines and register endpoints, if one of the region goes down the other stays up.
The following traffic routing methods are available in Traffic Manager:
- Priority: Select Priority when you want to use a primary service endpoint for all traffic, and provide backups in case the primary or the backup endpoints are unavailable.
- Weighted: Select Weighted when you want to distribute traffic across a set of endpoints, either evenly or according to weights, which you define.
- Performance: Select Performance when you have endpoints in different geographic locations and you want end users to use the “closest” endpoint in terms of the lowest network latency.
- Geographic: Select Geographic so that users are directed to specific endpoints (Azure, External, or Nested) based on which geographic location their DNS query originates from. This empowers Traffic Manager customers to enable scenarios where knowing a user’s geographic region and routing them based on that is important. Examples include complying with data sovereignty mandates, localization of content & user experience and measuring traffic from different regions.
- Multivalue: Select MultiValue for Traffic Manager profiles that can only have IPv4/IPv6 addresses as endpoints. When a query is received for this profile, all healthy endpoints are returned.
- Subnet: Select Subnet traffic-routing method to map sets of end-user IP address ranges to a specific endpoint within a Traffic Manager profile. When a request is received, the endpoint returned will be the one mapped for that request’s source IP address.
App Service plan pricing Tiers
There are a few categories of pricing tiers:
- Shared compute: Free and Shared, the two base tiers, runs an app on the same Azure VM as other App Service apps, including apps of other customers. These tiers allocate CPU quotas to each app that runs on the shared resources, and the resources cannot scale out.
- Dedicated compute: The Basic, Standard, Premium, and PremiumV2 tiers run apps on dedicated Azure VMs. Only apps in the same App Service plan share the same compute resources. The higher the tier, the more VM instances are available to you for scale-out.
- Isolated: This tier runs dedicated Azure VMs on dedicated Azure Virtual Networks, which provides network isolation on top of compute isolation to your apps. It provides the maximum scale-out capabilities.
- Consumption: This tier is only available to function apps. It scales the functions dynamically depending on workload. For more information, see Azure Functions hosting plans comparison
TO enable high throughput on a Logic App you can go to workflow settings and then choose High Throughput and click ON, this allows up to 300,000 executions every 5 minutes.
App Service Plans
The basic App Service Plan doesn’t support auto-scaling
Create a Linux virtual machine with Accelerated Networking
To create a Windows VM with Accelerated Networking, see Create a Windows VM with Accelerated Networking. Accelerated networking enables single root I/O virtualization (SR-IOV) to a VM, greatly improving its networking performance. This high-performance path bypasses the host from the datapath, reducing latency, jitter, and CPU utilization, for use with the most demanding network workloads on supported VM types. The following picture shows communication between two VMs with and without accelerated networking
Migrate databases to Azure with familiar tools
Azure Database Migration Service integrates some of the functionality of our existing tools and services. It provides customers with a comprehensive, highly available solution. The service uses the Data Migration Assistant to generate assessment reports that provide recommendations to guide you through the changes required prior to performing a migration. It’s up to you to perform any remediation required. When you’re ready to begin the migration process, Azure Database Migration Service performs all of the required steps. You can fire and forget your migration projects with peace of mind, knowing that the process takes advantage of best practices as determined by Microsoft.
Note: Using Azure Database Migration Service to perform an online migration requires creating an instance based on the Premium pricing tier.
Types of storage accounts
Azure Storage offers several types of storage accounts. Each type supports different features and has its own pricing model. Consider these differences before you create a storage account to determine the type of account that is best for your applications. The types of storage accounts are:
- General-purpose v2 accounts: Basic storage account type for blobs, files, queues, and tables. Recommended for most scenarios using Azure Storage.
- General-purpose v1 accounts: Legacy account type for blobs, files, queues, and tables. Use general-purpose v2 accounts instead when possible.
- Block blob storage accounts: Blob-only storage accounts with premium performance characteristics. Recommended for scenarios with high transactions rates, using smaller objects, or requiring consistently low storage latency.
- FileStorage (preview) storage accounts: Files-only storage accounts with premium performance characteristics. Recommended for enterprise or high performance scale applications.
- Blob storage accounts: Blob-only storage accounts. Use general-purpose v2 accounts instead when possible.
Azure Functions ARR affinity
If you create azure functions as part of the Basic app service plan, you can enable ARR Affinity which basically allows support for sticky sessions.
Azure App Service Access Restrictions
Access Restrictions enable you to define a priority ordered allow/deny list that controls network access to your app. The list can include IP addresses or Azure Virtual Network subnets. When there are one or more entries, there is then an implicit “deny all” that exists at the end of the list.
Auto Swap Staging Slots (Auto Swap isn’t supported in web apps on Linux.)
VNet Peering – connecting VM’s within the same Azure Region
Global VNet Peering – connecting VM’s across Azure Regions
Choose between Azure messaging services – Event Grid, Event Hubs, and Service Bus
Comparison of services
|Service||Purpose||Type||When to use|
|Event Grid||Reactive programming||Event distribution (discrete)||React to status changes|
|Event Hubs||Big data pipeline||Event streaming (series)||Telemetry and distributed data streaming|
|Service Bus||High-value enterprise messaging||Message||Order processing and financial transactions|
Event Grid is an eventing backplane that enables event-driven, reactive programming. It uses a publish-subscribe model. Publishers emit events, but have no expectation about which events are handled. Subscribers decide which events they want to handle.
Event Grid is deeply integrated with Azure services and can be integrated with third-party services. It simplifies event consumption and lowers costs by eliminating the need for constant polling. Event Grid efficiently and reliably routes events from Azure and non-Azure resources. It distributes the events to registered subscriber endpoints. The event message has the information you need to react to changes in services and applications. Event Grid isn’t a data pipeline, and doesn’t deliver the actual object that was updated.
Event Grid supports dead-lettering for events that aren’t delivered to an endpoint.
It has the following characteristics:
- dynamically scalable
- low cost
- at least once delivery
Azure Event Hubs is a big data pipeline. It facilitates the capture, retention, and replay of telemetry and event stream data. The data can come from many concurrent sources. Event Hubs allows telemetry and event data to be made available to a variety of stream-processing infrastructures and analytics services. It is available either as data streams or bundled event batches. This service provides a single solution that enables rapid data retrieval for real-time processing as well as repeated replay of stored raw data. It can capture the streaming data into a file for processing and analysis.
It has the following characteristics:
- low latency
- capable of receiving and processing millions of events per second
- at least once delivery
Service Bus is intended for traditional enterprise applications. These enterprise applications require transactions, ordering, duplicate detection, and instantaneous consistency. Service Bus enables cloud-native applications to provide reliable state transition management for business processes. When handling high-value messages that cannot be lost or duplicated, use Azure Service Bus. Service Bus also facilitates highly secure communication across hybrid cloud solutions and can connect existing on-premises systems to cloud solutions.
Service Bus is a brokered messaging system. It stores messages in a “broker” (for example, a queue) until the consuming party is ready to receive the messages.
It has the following characteristics:
- reliable asynchronous message delivery (enterprise messaging as a service) that requires polling
- advanced messaging features like FIFO, batching/sessions, transactions, dead-lettering, temporal control, routing and filtering, and duplicate detection
- at least once delivery
- optional in-order delivery
Has an SLA of 99.99% on the Basic and Standard tiers
RPO – Recovery Point Objective – The amount of data loss if a recovery needs to be done
RTO – Recovery Time Objective – The amount of time it takes to complete a recovery or restore
- Application Consistent – Here the backup takes into consideration any pending i/o operations and memory content operations. This allows the application to start in a consistent state after recovery.
- File System Consistent – This provides a consistent backup of disk files. Here the application needs to maintain its own mechanism to manage its consistency.
- Crash Consistent – Happens when the VM Shuts down at the time of the backup. Data exists on the disk at the time of the backup, but not guarantee on the disk consistency.
Azure Backup is good for retention periods of days, weeks, months and eve years.
Virtual Machines SLA’s
One VM = 99.9% availability
Two or more VM’s in an Availability Zone = 99.99% availability
Two or more VM’s in an Availability Set = 99.95% availability
Within 1 Region you may have 2 availability zones
So this can mean 2 Availability Zones each having 2 data centres.
Deploy 2 copies of your vm, 1 to a datacentre in zone1, the other vm to the other availability zone
- Fault domains (3 by default), ie separate server racks which have separate power etc. Your vm is deployed to say all 3 fault domains and then if a fault domain goes down your still good on the other 2.
- Update Domains (5 by default), when your vm might need updating, this concept means that some copies can be updated so that others stay up
If you add 6 vm’s to an availability set then the 6th vm would go into update domain 0 as the numbering starts at 0.
Azure Load Balancer (works at layer 4)
- Is used to distribute traffic to virtual machines
- Increases fault tolerance and availability for your application
- Works at the network layer
- Uses a public Ip address in front of the Azure Load Balancer
- The back end pool is literally your Virtual Machines
- The load balancer uses a health probe which needs the protocol, port, interval and threshold set
- The load balancer cannot be used to route traffic between resources in different regions, only the same region.
- If you want to achieve a higher availability of 99.99% then you should use a Standard Load Balancer instead of a Basic Load Balancer, and have at least 2 healthy virtual machines in the backend pool of the load balancer.
- The vm’s should be assigned a standard static public IP address
Application Gateway (works at layer 7)
- Web Traffic Load Balancer
- Works at the application layer
- URL Routing – example would be /video goes to backendpool1, /images goes to backendpool2
- SSL termination
WAF (web application firewall)
- Centralized protection for your web applications from common exploits and vulnerabilities
- If you want to deploy an application gateway you need an empty subnet available for your virtual network.
- SLA 99.5% – 2 or more medium or large instances
Azure Traffic Manager
- DNS based traffic load balancer
- Can Distribute traffic across regions
- You can use different traffic routing methods
- Priority – choose which region you prefer
- Geographic – direct end users to specific endpoints based on geographic location
- Multivalue – all healthy endpoints are returned to the user
- If your using Azure Site Recovery then you have to create an Azure Site Recovery Vault to store the data
- Premium Storage tier only allows storage of blobs, nothing else
- Default NSG Rules – deny all inbound from internet, allow all outbound to the internet, to stop subnets having access out add a new NSG rule and add a service tag of internet, destination port ranges * and then Action Deny with a low priority value of say 100 so that it over rules the default NSG outbound security rules
- If you want to get access to the Windows Graphic Device interface use Azure Batch
- When creating an Azure gateway the Ip Address has to be a public static ip address (sku standard)
- Using Powershell to get an azure keyvault secret
(Get-AZKeyVaultSecret -vaultname ‘myvaultname’ -name ‘mysecretname’ ).SecretValueText
- Azure AD Conditional access requires Premium Tier on Azure AD
- When you set up ASR in another region and point it to some VMs, it installs the Azure Site Recovery extension called Mobility Service in the source VMs
- Azure Site Recovery is for replicating Virtual or Physical Machines from various sources. It does NOT support Azure App Services. But it does support Hyper-V and VMWare Virtual Machines, and Windows or Linux Physical Machines.
- ASR requires port 443 and 9443 in order to do it’s replication from the source servers
- To replicate Hyper-V virtual machines between two on-premises data centers, you need SCVMM to be on both systems already
- ASR can replicate sites between regions as long as they are in the same geography. It would not support US East machines being replicated to Japan East because it crosses a geographic boundary.
- VMs across multiple Availability Zones provides the highest Microsoft SLA at 99.99%. Using availability sets provides 99.95% SLA. Standalone VMs behind a load balancer does not provide an SLA. Using Azure Site Recovery provides Business Continuity, and not a high-availability.
- How does SQL Database implement high availability at the Premium Tier?
The Premium tier of SQL Database runs the database in a 4-node Always On Availability Group Cluster. This has one primary database node with 3 secondary processes keeping copies of the data.
- Using SQL Database Always On Encryption with Deterministic Encryption. This allows the database to perform database operations on the table such as joins and equality tests, while keeping the data encrypted in the table and from regular application reads. SQL Database Always On Encryption with Randomized Encryption does not allow table operations
- With Storage Queues, calling UpdateMessage can be used to extend the lease and prevent the message from being given to another process. RenewLock is for Service Bus Queue and not Storage Queues. Rearchitecting the application may not be a simple solution, although it may be wise.
- You can scale a web app using metrics provided by Application Insights, which needs to be implemented before you can enable such scaling
- Transparent Data Encryption allows the data stored on the disk to be encrypted and it supports geo-replication and geo-restore. Always Encrypted will not suffice as this is focused on transport encryption (data in transit is encrypted)
- Azure Confidential Compute (ACC) is only supported on the DC-Series VMs, Azure Confidential Compute allows code and data in the processor to be secured when running. Azure Confidential Compute is not supported on any other VM series except DC-series.
- SendGrid is an email solution which provides email functionality via distribution groups as well as metric gathering
- Azure AD Privileged Identity Management is a tool that will allow you to see who has elevated permissions within your environment. You can examine the history of that access, and whether they use those permissions. And you can ask users to justify the need for those elevated permissions in a security review.
- Azure Site Recovery (ASR) does not support the recovery of most PaaS solutions such as Azure Storage and Azure App Services. ASR is for infrastructure workloads such as Windows and Linux VM’s, SAP, VMWare, Sharepoint, IIS, and SQL Server
- Function Keys and Azure API Management can both protect a Function app’s public endpoint. Function keys are unique codes that can be required to be used when calling an endpoint. This only protects the endpoint when the function key is a true secret. Azure API Management can be put in front of the function and require other forms of authentication such as Azure AD or OAuth. Functions do not support Shared Access Signatures (SAS).
- Shared Access Signatures (SAS) and Azure API Management can both protect a Service Bus’ public endpoint. Shared Access Signatures (SAS) are unique codes that can be required to be used when calling an endpoint. This is why they are called “shared”. This only protects the endpoint when the SAS is a true secret. Azure API Management can be put in front of the function and require other forms of authentication such as Azure AD or OAuth. Service Bus does not support Function Keys or Multi-Factor Authentication.
- Always Encrypt allows you to choose which columns to encrypt, and SQL Database will do the work for you. When using a command line, the data will come out encrypted. But a trusted application can see the data, and use it in JOINs, SELECTs, and WHERE clauses. Application side encryption will not allow JOINs, etc. A Trusted Execution Environment (TEE) is not used for SQL Database service. All data is stored at rest encrypted using TDE by default.