1:10:15
Azure API Management Deep Dive
John Savill's Technical Training
Overview
This video provides a comprehensive deep dive into Azure API Management, explaining its role as a crucial abstraction layer between API providers and consumers. It covers the core components like the control plane and the API Gateway, emphasizing its capabilities for managing, securing, and scaling APIs. The discussion extends to how API Management handles diverse API backends, including cloud and on-premises resources, and its integration with virtual networks for private API access. Advanced features like policy expressions, self-hosted gateways for hybrid scenarios, and the concept of workspaces for federated management are also explored, alongside the developer portal and its complementary relationship with Azure API Center for API inventory and governance.
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Chapters
- APIs are ubiquitous, with providers creating them and consumers (applications) using them.
- APIs can be hosted in various locations, including the cloud and on-premises.
- Key challenges in API consumption include discoverability, security, understanding capabilities, and governance.
- Azure API Management acts as an abstraction layer to address these challenges, sitting between consumers and providers.
Understanding the fundamental problems that API Management solves helps appreciate its value and the specific features it offers to streamline API interactions.
An organization has many APIs hosted in different clouds and on-premises, and developers struggle to find, secure, and understand how to use them effectively.
- The control plane, managed via Azure Resource Manager (ARM), is used for defining APIs, policies, and backends through tools like the portal, CLI, or templates.
- The API Gateway is the runtime component that sits in the middle, receiving requests and forwarding them to the appropriate backend API.
- The Gateway applies policies on both inbound and outbound traffic, abstracting the backend API's complexity.
- When deployed, Azure API Management creates an instance with a managed Gateway, typically in a specific Azure region.
Knowing the distinct roles of the control plane and the gateway clarifies how API Management is configured and how it functions at runtime to process API requests.
A developer uses the Azure portal (which interacts with the control plane via ARM) to add a new API definition and then configures policies that the API Gateway will enforce.
- The managed API Gateway can be scaled by increasing the number of units, and higher tiers support distribution across Availability Zones for data center-level resiliency.
- For multi-region deployments (available in Premium tiers), API Management instances can be deployed in multiple Azure regions, each with its own managed Gateway.
- A globally available URL, managed by Azure Traffic Manager, directs requests to the lowest latency regional Gateway based on performance routing.
- Traffic Manager ensures resiliency by health-probing gateways and redirecting traffic away from unhealthy instances.
Understanding the gateway's scalability and multi-region capabilities is crucial for ensuring high availability, performance, and disaster recovery for your APIs.
An API Management instance deployed in Europe and East US will have its own regional URLs, and Traffic Manager will direct a user in Europe to the European Gateway for lower latency.
- Azure API Management supports a wide variety of API types (HTTP, WebSockets, GraphQL, gRPC, SOAP, REST) and can connect to backends hosted anywhere, including Azure services and on-premises.
- For private backends within a virtual network (VNet), API Management can be injected into a delegated subnet, allowing the gateway to communicate with resources inside the VNet.
- To enforce the use of API Management, backend APIs should be secured to prevent direct access, for example, by whitelisting the API Management Gateway's IP or using specific authentication.
- API Management can connect to backends via public IPs, private IPs (requiring VNet integration), or through secure hybrid connections like ExpressRoute or VPN.
This section highlights the flexibility of API Management in integrating with virtually any backend, whether it's in the cloud or on-premises, and the necessary network configurations for private access.
An API hosted on an Azure Function within a VNet can be made accessible through API Management by integrating the gateway into the VNet via a delegated subnet.
- Policies are powerful rules applied at the gateway to transform requests and responses, enforce security, and control API behavior.
- Policies can be used for various functions like URL rewriting, retries, circuit breakers, rate limiting, authentication, and content validation.
- Policy expressions allow embedding C# code for more advanced logic, enabling custom transformations or dynamic decisions.
- AI capabilities like semantic caching for LLMs can be implemented using policies and external caches, significantly improving performance and reducing costs.
Policies are the core mechanism for customizing API behavior, adding value, and implementing complex logic without modifying the backend services themselves.
A policy can be configured to rewrite the incoming request path from '/widget' to '/delete-widget' before forwarding it to the backend Azure Function.
- API Management supports authentication mapping, allowing different authentication methods for clients accessing the gateway versus the gateway accessing the backend.
- A self-hosted gateway can be deployed in remote networks (on-premises or other clouds) to provide API Management functionality locally, avoiding data path hairpinning through Azure.
- The self-hosted gateway requires an outbound connection to Azure for configuration but handles data traffic locally, optimizing latency and security.
- Self-hosted gateways can be made available on public or private endpoints, offering flexibility for hybrid environments.
These features address advanced scenarios like managing credentials across different security domains and optimizing network traffic flow in hybrid and multi-cloud setups.
An application in a private on-premises network can use a self-hosted gateway to access a local API, with policies applied locally, without sending traffic to the Azure-managed gateway.
- Workspaces allow for the delegation of API management to different teams, each with its own gateway configuration, enabling a federated governance model.
- The Developer Portal serves as a self-service hub for developers to discover, learn about, and test APIs, and it is highly customizable.
- Azure API Center is a design-time solution for API inventory and governance across all APIs, complementing the runtime capabilities of API Management.
- API Management offers various tiers (Basic, Standard, Premium) with differing features, SLAs, and scaling options, influencing the choice of SKU based on requirements.
These components provide essential tools for managing API development lifecycles, fostering collaboration, and ensuring organizational standards are met across diverse API landscapes.
A central IT team can use workspaces to delegate specific API sets to different application development teams, maintaining overall governance while allowing teams agility within their workspace.
Key takeaways
- Azure API Management acts as a central gateway to manage, secure, and publish APIs, abstracting backend complexity.
- The API Gateway is the core runtime component responsible for request routing and policy enforcement.
- Resiliency and scalability are achieved through multi-region deployments, Availability Zone support, and Traffic Manager integration.
- API Management can connect to any API backend, including cloud and on-premises services, with VNet integration for private access.
- Policies are the primary tool for customizing API behavior, adding logic, and implementing security measures without altering backend code.
- Self-hosted gateways enable API Management functionality in remote networks, optimizing latency and security for hybrid scenarios.
- Workspaces facilitate federated API management, balancing central governance with team agility.
- The Developer Portal and Azure API Center provide essential tools for API discovery, documentation, and lifecycle governance.
Key terms
API GatewayControl PlanePoliciesManaged GatewaySelf-hosted GatewayTraffic ManagerVirtual Network (VNet) IntegrationDelegated SubnetWorkspacesDeveloper PortalAzure API CenterPolicy Expressions
Test your understanding
- What is the primary role of the Azure API Management Gateway?
- How does Azure API Management provide resiliency for its managed gateways?
- What are the key challenges that Azure API Management aims to solve for API consumers and providers?
- How can Azure API Management be used to access APIs hosted within a private virtual network?
- What is the purpose of policies in Azure API Management, and what are some examples of their use?
- When would you consider using a self-hosted gateway instead of a managed gateway?
- How do workspaces in Azure API Management help organizations manage their APIs effectively?