Implication of API Gateway‑Sprawl

Around 10 years back I was assigned to rationalize the Enterprise Service Bus Portfolio (Primarily BizTalk Servers) of an American investment bank and financial services holding company. This specific customer was experiencing ESB hell or ESB Mess. Each project/product and Business unit had their own ESB, hence managing ESB portfolio was costlier. Now when I see API management trends, I do smell similar challenge on our customer and enterprise too. Hence I thought writing some of my opinion based on prior experience on what value it brings for having multiple APIM products.

As per CAGR report, the global APIM market is expected to grow from USD 5.1 Billion by 2023. The key driving factors for the API Management market are as below.

  • Growing Demand for API-Led Connectivity
  • Need for Public and Private APIs to Accelerate Digital Transformation
  • Opportunities for the API Management market
  • Low-code platform for API development
  • API Management solutions powered with advanced analytics capabilities

Though enterprises are ending up adopting multiple APIM for several very good reasons and it is becoming a trend now, but the same time It’s becoming more expensive to run multiple API gateways and management. This blog discuss some of  the subject around,

  • What are the possible reason for Heterogeneous and diversified API gateways?
  • What challenges have we created for ourselves by using Multiple API gateways on enterprise?
  • How can we deal with the complexities of “API Gateway‑sprawl”?
  • Can we consolidate without compromising performance, stability, and functionality?

Why heterogeneous API gateways?

1. Two-Tier Gateway: Two‑Tier (multi‑layer) gateway pattern enable clear separation of roles for multiple gateways. An external gateway that controls the traffic between the enterprise and the outside world, and an internal gateway for various applications and systems flows inside organizations. Key solution rationale behind this approach are,

    • Cyber Security: An external-facing API gateway can have stringent security policies in terms of compliances and best practices whereas the internal API gateway may have different set of policies for internal applications and APIs. For example, the API Trust level for Vendor and Customer may not be the same for the internal API developer.
    • Many independent points of failure in case of breach: In the case of a breach or cyberattack on one, the other can keep running so all applications don’t come to a complete halt hence increasing the availability of SLA.
    • Cost Optimization: Use of open source reverse proxy for internal gateway for instance Ocelot /NGINX may provide less features but can reduce a lot of cost.  
    • API-first externally, but not at all internally: As part of legacy modernization journey, enterprise core business logics may have behind API and a Gateway, but in order to expose it to external consumer, creating another layer of API Gateway make sense.

2. Cloud Transformations: While transitioning to cloud, major of enterprise prefer to use Cloud native gateway over legacy or traditional gateways. Also certain cloud native service come as a pre-packaged API gateway for instance Azure IOT central comes with Azure APIM which is an integral part.

3. Organizational Structures: For ease of management and operation, major of enterprise have multiple Lines of Business or Business Unit. The supporting applications and LOB’s IT investment depends on nature of business and it have a direct impact of API gateway too. There are quite possibilities that, API gateways used for Manufacturing LOB may not have the same API gateway for Marketing LOB. Also inorganic business growth strategies like merger and acquisitions too one of the important factor for having Gateway‑sprawl.

4. Filling Gap of Modern need: It is evident that, not all API gateway product provide or meet all the need of enterprise or the product chosen may not evolved over a period of time. For example, if a Solution evolved over a period of time using Azure API gateway needed to support grpc routing which is not supported by Azure, then as an alternate solution use to have another API Gateway like Nginx or Kong accepting grpc request and routing to API gateway.

5. Vendor Lock-In: The vendor lock-in problem in cloud computing is the situation where customers are dependent (i.e. locked-in) on a single cloud provider technology implementation and cannot easily move in the future to a different vendor without substantial costs, legal constraints, or technical incompatibilities. In order to mitigate the Risk CXO always prefer to have multiple cloud gateway pertaining to the solutions need.

6. True Containerization: Looking to the advantages of containerizations and hybrid clouds, the API and API gateways can be containerized and deploy as an independent unit.  This is now becoming a trend on AKS creating possibilities of having heterogeneous API gateways

7. Types of Environment: Historically it has been always recommended to segregate different type of environment as Dev, Test, Staging and Production. As part of best practices there are many enterprises who segregate the API gateways according to the environment. This benefit to apply a group of policies based on specific environment. 

8. Microservice Architecture: In a microservices architecture, the client apps usually need to consume functionality from more than one Microservice. If that consumption is performed directly, the client will need to handle multiple Microservice endpoints to call. 

An API gateway try to solve following architectural challenges listed as below ,

  • Coupling with each Microservice
  • Too many round trips
  • Security issues
  • Cross-cutting concerns

Key Implications of APIM Mess

Having multiple API gateways will typically increase the operational cost and governance overhead. Some of pain points of having fragmented API gateways as listed below: 

  1. High cost of managing API lifecycles
  2. Time-consuming and inflexible to API driven development.
  3. Partners may have to use multiple gateways to complete transactions.
  4. Duplicate of efforts on configuration and management of policies
  5. Inconsistent branding across channels
  6. Retention of multiple skills
  7. Dissatisfied customer experience
  8. No single source of truth for API policies
  9. Lack of centralized visibility into who is consuming APIs
  10. Resists Reuse.
  11. Fragmented view on API economy
  12. Issue on Troubleshooting or doing Root cause of API failure.
  13. Reduced support efficiency
  14. Data inconsistency across systems.
  15. Developers onboarding, off boarding and their management in different portal

How to Deal with “API Gateway‑sprawl”?

Though existence or embarking on multiple API gateways for a cause is not at all a bad practice the same time standardizing on a single gateway is not realistic for largest organizations. This paper recommend that the enterprises should understand the implication of having multiple gateway and should avoid or eliminate. It is good to be aware and provide key guidelines as part of Enterprise Architecture on when and what circumstance solution should use Single Gateway Vs multiple gateway solutions. It is always an obvious question is When one API gateway is adequate? If the reasons and situation are offered on Why Section of this paper is not your organization’s situations, then you may wish to start with a single API gateway segment, then re-evaluate the need for multiple segments in the future. This not only simplifies your automated deployments; it will also reduce operating costs by limiting your API gateway footprint. Consider the reasons for multiple API gateways with a clear weigh on the benefits and challenges to determine what the right approach is for your organization.

Another options to deal with Multiple API gateways is to invest on an Enterprise API gateway Enterprise Hub or similar pattern. There are few products in this category which are evolving are,

  • Rapid API Enterprise Hub
  • AMPLIFY
  • SAP API Business Hub

Below diagram provide a high level reference architecture most of these product adheres.

The value Proposition of API Enterprise Hub revolve around

  • Governance and safety
  • Consumption visibility
  • Cost
  • Debugging and monitoring

Summary

A majority of IT leaders today are using API first development approach or are planning to invest on an API Management Product as a handy tool for competitive distinction. Whether you are looking to simplify ‘traditional’ approach having few manageable API gateways or seeking to solve governance and cost optimization challenges you really need to think and justify the business benefit of having multiple APIM.






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