An API gateway is at the core of how APIs are managed, secured, and presented within any web-based system. Although the technology has been in use for many years, it has not always kept pace with recent developments within the cloud native space, and many engineers are confused about how a cloud native API gateway relates to Kubernetes Ingress or a Service load balancer. Join this session to learn about: – The evolution of API gateways over the past ten years, and how the original problems they were solving have shifted in relation to cloud native technologies and workflow – Current challenges of using an API gateway within Kubernetes: scaling the developer workflow; and supporting multiple architecture styles and protocols – Strategies for exposing Kubernetes services and APIs at the edge of your system – A brief guide to the (potential) future of cloud native API gateways

1. The Past, Present, and Future of
Cloud Native API Gateways
Daniel Bryant

2. tl;dr
• Edge gateways have undergone a series of evolutions, driven by architecture
• “Cloud native” (microservices/K8s) changes architecture and workflow
• Chose your cloud API gateway solution intentionally
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3. @danielbryantuk
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4. 4
Edge: The boundary between your
data center and your user(s)

5. 5
Thesis: The evolution of the edge has
been driven by application architecture

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The past:
A trip down memory lane

7. 7
~1995

8. Application Architecture in the ‘90s
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9. Hardware Load Balancer
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User Systems administrators
Purpose High availability / scalability
Key Features
Load balancing
(round robin, sticky sessions)
Health checks

10. 10
~2000

11. Similar application architecture
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12. 12
20022001

13. Software Load Balancer
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User
Systems administrators
(“pre DevOps”)
Purpose High availability / scalability
Key Features
Load balancing
Health checks
Observability

14. 14
~2005

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Ecommerce
0
75
150
225
300
2000 2005 2010 2015 2019
Amazon Revenue,
Billions

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18. The Application Delivery Controller (ADC)
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19. Application Delivery Controllers
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User Systems administrators
Purpose
High availability and
application acceleration
Key Features
SSL offload, caching,
compression + load balancing

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https://www.flickr.com/photos/pchow98/5518600886

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~2010

22. The proliferation of APIs
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2005: API launched 2008 2009

23. API Gateway (1st Gen)
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User
Systems administrators &
API developers
Purpose
Expose business APIs to
broader ecosystem
(“API management”)
Key Features
L7 routing (e.g., throttling),
Publishing, Dev Portal,
Analytics, Monetization

24. 24
~2015

25. 25

26. Mini-services
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27. API Gateway (2nd Generation)
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28. API Gateway (2nd Generation)
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User
Systems administrators &
API developers
Purpose
Centralize cross-cutting app
concerns
Key Features
Authentication, rate limiting,
monitoring + routing

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Present day:
Cloud-native apps

30. Cloud-Native Microservices
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• Modularisation (“microservices”)
• Built, released, & operated by
independent application teams
• Scaled independently

31. App Architecture: A Spectrum of Services
• Different locations (K8S, VMs, FaaS)
• Different protocols (gRPC, HTTP, WebSockets, TCP)
• Different load balancing requirements (sticky
sessions, round robin)
• Different authentication requirements
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32. Cloud Gateway
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Real-time Service
Discovery
Need ADC-like traffic management
capabilities: timeouts, retries, rate
limiting, load balancing, caching, …
Need API Gateway-type
management capabilities:
authentication, developer
portal, metrics, …
1
2
3

33. “Microservices” lead to an even bigger change.
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34. 34
Developers are on call.

35. Microservices: Full Cycle Development
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• App teams have full responsibility (and authority) for
delivering a service
• Increases agility by accelerating the feedback loop.
• https://netflixtechblog.com/full-cycle-developers-at-netflix-a08c31f83249

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This is a change in workflow.

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Thesis: The evolution of the edge will be
driven by application architecture and the
application development workflow.

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Two Biggest
Challenges

39. Challenge #1: Scaling Edge Management
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Development
Team
Operations / Platform Team

40. Challenge #1: Scaling Edge Management

41. Challenge #2: Supporting Diverse Edge Requirements
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Three Strategies

43. Three Strategies for the Edge with Kubernetes
#1: Deploy an Additional Kubernetes API Gateway
#2: Extend Existing API Gateway
#3: Deploy an in-Cluster Edge Stack
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https://www.getambassador.io/resources/strategies-managing-apis-edge-kubernetes/

44. #1 Deploy an Additional Kubernetes API Gateway
• Simply deploy an additional “in-cluster” gateway
• Below the existing gateway
• Below the load balancer
• Management
• Development teams responsible
• OR existing ops team manages this
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45. #1 Deploy an Additional Kubernetes API Gateway
• Pros
• There is minimal change to the core edge infrastructure.
• Incremental migration easily
• Cons
• Increased management overhead of working with
different components
• Challenging to expose the functionality to each
independent microservice teams
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46. #2 Extend Existing API Gateway
• Implemented by modifying or augmenting the existing API
gateway solution
• Enable synchronization between the API endpoints and
location of k8s services
• Custom ingress controller for the existing API Gateway or
load balancer
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47. #2 Extend Existing API Gateway
• Pros
• Reuse the existing tried and trusted API gateway
• Leverage existing integrations with on-premises
infrastructure and services
• Cons
• Workflows must change to preserve a single source of
truth for the API gateway configuration
• Limited amount of configuration parameters via
Kubernetes annotations
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48. #3 Deploy an In-Cluster Edge Stack
• Deploy Kubernetes-native API gateway with
integrated supporting edge components
• Installed in each of the new Kubernetes clusters,
replacing existing edge
• Ops team own, and provide sane defaults
• Dev teams responsible for configuring the edge
stack as part of their normal workflow
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49. #3 Deploy an In-Cluster Edge Stack
• Pros
• Edge management is simplified into a single stack
• Supports cloud native best practices: “single
source of truth”, GitOps etc
• Cons
• Potentially a large architectural shift
• Platform team must learn about new proxy
technologies and edge components
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50. 50
Wrapping Up

51. In Conclusion
• Edge/API gateways have undergone a series of evolutions, driven by architecture
• Hardware -> software
• Networking Layer 4 -> Layer 7
• Centralized management -> decentralised
• Adopting microservices/Kubernetes changes workflow. We need to:
• Scale edge management
• Support multi-protocol and cross-functional requirements
• Chose your solution intentionally
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52. Many thanks!
• Learn more:
• https://www.getambassador.io/learn/building-kubernetes-platform/
• https://www.getambassador.io/podcasts/
• https://blog.getambassador.io/
• Find me in:
• Datawire OSS Slack: http://d6e.co/slack
• Twitter @danielbryantuk
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