This chapter covers Azure Preview Features and Updates, an important topic under the 'Azure Management Governance' domain. For the AZ-900 exam, this objective area carries approximately 5-10% weight. You will learn how to identify preview features, understand their lifecycle, and know the key differences between preview and general availability (GA) states. The exam tests your ability to recognize when preview features are appropriate and what limitations apply, such as lack of SLAs and potential breaking changes.
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Imagine you're a restaurant owner planning to add a new dish to your menu. Before committing fully, you offer it as a 'chef's special' for a limited time. Customers can try it, give feedback, and you can tweak the recipe based on their reactions. Some customers love the exclusivity of trying something new, while others prefer sticking to the tried-and-tested menu items. The chef's special isn't on the main menu yet—it's previewed to a select audience. If it's a hit, it becomes a permanent menu item; if not, it's quietly removed. In Azure, preview features work similarly. They are new services or capabilities released for early testing before general availability (GA). Customers can enable them to test, provide feedback, and influence the final product. However, preview features are not covered by SLAs and may have limited support, just like a chef's special that might change or disappear. This analogy captures the mechanism: controlled exposure, feedback loop, no guarantees, and eventual graduation or retirement.
What Are Azure Preview Features?
Azure Preview Features are new services, features, or updates that Microsoft releases for early testing and feedback before making them generally available (GA). They allow customers to try out upcoming capabilities, provide input, and help shape the final product. Preview features are not ready for production use because they may have limited functionality, performance issues, or breaking changes.
The Business Problem Solved
Cloud innovation moves fast. Microsoft releases hundreds of new features each year. Preview features solve two problems: (1) Microsoft gets real-world testing and feedback from a diverse set of customers, and (2) customers get early access to cutting-edge technology, enabling them to plan for future adoption and influence the roadmap.
How Preview Features Work
Release Phase: A feature enters preview, often with a label like "Preview," "Public Preview," or "Private Preview."
Opt-In: Customers must explicitly enable the preview feature, either in the Azure portal, via Azure CLI, or using Azure PowerShell.
Usage and Feedback: Customers use the feature, report bugs, and suggest improvements through Azure Feedback forums or support channels.
Iteration: Microsoft iterates based on feedback, potentially making breaking changes.
Graduation or Retirement: After a period, the feature either becomes GA (with full support and SLA) or is retired if not viable.
Types of Preview
Private Preview: Limited to a select group of customers invited by Microsoft. Requires NDA often. Not accessible to everyone.
Public Preview: Available to all Azure customers. Can be accessed via Azure portal or feature registration. No SLA, but broader feedback.
Key Components and Limitations
No SLA: Preview features are not covered by any service level agreement. Uptime, performance, and support are not guaranteed.
No Support Guarantees: Support may be limited or through community forums only.
Breaking Changes: Microsoft may change or remove features without notice.
Limited Regions: Preview features may only be available in specific Azure regions.
Pricing: Some preview features are free during preview, but pricing may change upon GA.
Comparing Preview to General Availability
GA features: Fully supported, have SLAs, are stable, and are ready for production workloads.
Preview features: Experimental, no SLA, subject to change, and not production-ready.
Azure Portal and CLI Touchpoints
Azure Portal: Navigate to any service blade; look for a "Preview" label or "Try preview" button. Also, the "Preview features" blade under Subscriptions lists available previews.
Azure CLI: Use commands like az feature list or az feature register to manage preview features.
Azure PowerShell: Use Get-AzProviderFeature and Register-AzProviderFeature.
REST API: GET /subscriptions/{subscriptionId}/providers/Microsoft.Features/features.
Concrete Business Scenario
A company wants to test Azure's new Managed Instance for Apache Cassandra before moving their production database. They enable the public preview, run test workloads, and find a bug. They report it via Azure Feedback. Microsoft fixes the bug and later releases the feature as GA. The company then confidently migrates their production workload.
Step-by-Step: Enabling a Preview Feature
Identify the Preview Feature: Go to the Azure portal, search for "Preview features" under your subscription. Or use CLI: az feature list --query "[?properties.state=='NotRegistered']".
Register the Feature: Click "Register" in the portal or run az feature register --namespace Microsoft.Compute --name InGuestPatch.
Verify Registration: Check status; it may take a few minutes. Use az feature show.
Re-register Resource Provider: Some features require re-registering the resource provider. Use az provider register --namespace Microsoft.Compute.
Use the Feature: Navigate to the relevant service and leverage the new capability.
Important Defaults and Limits
Preview features are not enabled by default; you must opt in.
Registration is per subscription.
Some preview features have quotas or caps.
Preview features may be removed after a period if not adopted.
Exam Relevance
For AZ-900, you need to understand the concept of preview features, their limitations (no SLA, breaking changes), and how they differ from GA. The exam may present scenarios where you must decide whether to use a preview feature for a production workload (answer: no). Also, know that preview features are available in the portal with a "Preview" label.
Identify the Preview Feature
First, you need to know which preview features are available. In the Azure portal, navigate to your subscription, then select 'Preview features' under 'Settings'. You'll see a list of features with their state (Registered, NotRegistered, or Pending). Alternatively, use Azure CLI: `az feature list --namespace <provider> --query "[?properties.state=='NotRegistered']"`. This step is crucial because you must explicitly opt in; preview features are not automatically available.
Register the Preview Feature
Once you've identified the feature, register it. In the portal, click the feature and select 'Register'. For CLI, use `az feature register --namespace <provider> --name <featureName>`. This tells Azure that you want to try the preview. Behind the scenes, Azure updates the feature's state to 'Pending' and then 'Registered' once the registration propagates. This may take a few minutes. Note that registration is per subscription.
Verify Registration Status
After registration, verify the status. In the portal, refresh the preview features list; the state should change from 'NotRegistered' to 'Registered'. Using CLI: `az feature show --namespace <provider> --name <featureName> --query properties.state`. A state of 'Registered' means you can now use the feature. If it shows 'Pending', wait and try again. Azure does this to ensure the feature is enabled across all backend services.
Re-register the Resource Provider
Some preview features require re-registering the resource provider to make the new APIs available. In the portal, go to your subscription, select 'Resource providers', find the relevant provider (e.g., Microsoft.Compute), and click 'Re-register'. For CLI: `az provider register --namespace <provider>`. This step ensures the provider's API version includes the preview feature. Without this, you may get errors when trying to use the feature.
Use the Preview Feature
Now you can leverage the preview feature. For example, if you registered a new VM size, you can now create a VM with that size. In the portal, you'll see the new option; in CLI or PowerShell, you can specify the new SKU. Remember that preview features may have limited regions or quotas. Always test in a non-production environment. Monitor for any breaking changes as Microsoft iterates.
Scenario 1: Early Adoption of Azure Kubernetes Service (AKS) Features
A tech startup wants to use the latest AKS features like cluster autoscaler improvements that are in public preview. They enable the preview feature in their development subscription. The team configures a test cluster and runs load tests. They find that the autoscaler reacts faster than the GA version. They provide feedback through Azure Feedback. However, during the preview, Microsoft releases a breaking change that requires updating the cluster configuration. The team adapts quickly because they are not in production. Once the feature reaches GA, they confidently upgrade their production cluster. Cost: no additional cost during preview. Common mistake: using preview features in production without contingency plans, leading to downtime during breaking changes.
Scenario 2: Testing Azure SQL Database Hyperscale Tier Preview
A medium-sized enterprise considers migrating their large database to Azure SQL Database. They hear about the Hyperscale tier in public preview. They enable the preview feature and create a Hyperscale database. They run performance benchmarks and find it meets their needs. They also test backup/restore, which works well. They report a minor issue with query performance under heavy load. Microsoft fixes it before GA. The enterprise then moves their production database to Hyperscale after GA. Scale: the Hyperscale tier supports up to 100 TB. Cost: during preview, they pay only for compute and storage at discounted rates. What goes wrong: if they had not tested thoroughly, they might have encountered the performance issue in production.
Scenario 3: Evaluating Azure Confidential Computing Preview
A healthcare company needs to process sensitive patient data in the cloud. They consider Azure Confidential Computing, which is in preview. They enable the preview and deploy a test workload using Confidential VMs. They validate that data is encrypted in memory. They provide feedback on ease of use. The preview helps them plan their security posture. However, they notice that not all regions support the preview, so they must choose a supported region. Once GA, they roll out to production. Common pitfall: assuming preview features have the same compliance certifications as GA features; they may not, so the company had to check with their compliance team.
Objective Code: AZ-900: Describe Azure Preview Features and Updates (Sub-objective of 'Describe Azure Management and Governance')
The exam expects you to: (1) Identify the purpose of preview features, (2) Understand the differences between preview and GA, (3) Know the limitations of preview features (no SLA, breaking changes, limited support), (4) Recognize that preview features must be explicitly enabled.
Common Wrong Answers and Why
'Preview features are production-ready.' Why candidates choose: They think 'Preview' means 'almost ready' but Azure explicitly states preview features are not for production. The exam tests this distinction.
'Preview features have SLAs.' Why: Candidates confuse preview with GA. Microsoft never provides SLAs for preview features.
'Preview features are automatically enabled for all subscriptions.' Why: Some assume it's opt-out, but it's opt-in. The exam may present a scenario where a user cannot see a feature because they haven't registered.
'Preview features cannot be used at all.' Why: Overcaution. Preview features can be used for testing and evaluation, just not production.
Specific Terms and Values
'Preview' label in the Azure portal.
'Public Preview' vs 'Private Preview': Public is open to all; private is invite-only.
'General Availability (GA)': The stable, supported state.
'No SLA': Memorize this phrase.
'Breaking changes': A key risk.
Edge Cases and Tricky Distinctions
Preview features may become GA with different pricing. The exam might ask if preview features are free (they can be, but not guaranteed).
Some preview features are region-restricted. The exam may present a scenario where a feature is unavailable in a region.
Preview features may be deprecated. The exam might ask about the risk of using preview features long-term.
Memory Trick: 'PEN' (Preview = Evaluate, Not production)
P - Preview features are for Piloting and Planning.
E - Enable them explicitly.
N - No SLA, Not for production.
Decision Tree for Exam Questions
If the question asks: 'Should you use this preview feature for a production workload?' Answer: No, because no SLA and potential breaking changes. If the question asks: 'How do you access a preview feature?' Look for 'Register' or 'Enable' in the options. If the question asks about SLA: Preview features have no SLA. If the question asks about support: Preview features may have limited or no support.
Preview features are new capabilities released for early testing before General Availability (GA).
Preview features are not covered by any SLA and should not be used in production workloads.
Preview features must be explicitly enabled (opt-in) per subscription.
Preview features may have breaking changes, limited regions, and no guaranteed support.
Public Preview is open to all; Private Preview is by invitation only.
The Azure portal labels preview features with a 'Preview' badge.
You can manage preview features using Azure CLI (az feature) or PowerShell.
Preview features may become GA with different pricing or may be deprecated.
These come up on the exam all the time. Here's how to tell them apart.
Public Preview
Available to all Azure customers
No NDA required
Can be accessed via Azure portal or CLI
Broader feedback collection
Usually free during preview
Private Preview
Limited to invited customers only
Often requires signing an NDA
Access is granted by Microsoft
Targeted feedback from specific customers
May have more stability but still no SLA
Mistake
Preview features are fully supported by Microsoft Support.
Correct
Preview features often have limited or no support. Microsoft may provide support through community forums, but they are not covered by standard support plans.
Mistake
Once a preview feature is enabled, it remains available forever.
Correct
Preview features can be deprecated or removed by Microsoft at any time. They are not guaranteed to become GA.
Mistake
Preview features are free of charge always.
Correct
Some preview features are free during preview, but Microsoft may introduce charges upon GA. Always check the pricing page.
Mistake
You can use preview features in production if you are careful.
Correct
Microsoft explicitly advises against using preview features in production because they may have breaking changes, no SLA, and limited functionality.
Mistake
All preview features are available in all Azure regions.
Correct
Preview features often launch in a limited set of regions first. You must check regional availability before enabling.
No, you should not use preview features in production. Microsoft explicitly states that preview features are not production-ready because they may have limited functionality, no SLA, and could undergo breaking changes. Always use preview features in non-production environments for testing and evaluation only.
No, preview features do not have any service level agreement (SLA). Microsoft does not guarantee uptime, performance, or support for preview features. Only features that are Generally Available (GA) have SLAs. Always check the SLA page for GA services.
To enable a preview feature, go to the Azure portal, navigate to your subscription, select 'Preview features' under Settings, find the feature, and click 'Register'. Alternatively, use Azure CLI: `az feature register --namespace <provider> --name <featureName>`. You may also need to re-register the resource provider.
Public Preview is available to all Azure customers without an NDA. Private Preview is limited to a select group of customers invited by Microsoft, often requiring a non-disclosure agreement. Private Preview may offer more stability but still has no SLA.
Many preview features are free during the preview period, but this is not guaranteed. Microsoft may charge for some preview features or introduce pricing when they become GA. Always check the official pricing page for the specific preview feature.
Yes, Microsoft may deprecate or remove a preview feature at any time without notice. Not all preview features become GA. If a feature is removed, you may lose access to your configurations or data. Always have a migration plan.
In the Azure portal, preview features are marked with a 'Preview' label. You can also check the 'Preview features' blade under your subscription. In documentation, preview features are noted as 'in preview' or 'public preview'. The Azure CLI and PowerShell also indicate preview status.
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