How API7 Gateway Overcomes Exceptions with High Availability Strategies
Published: 2024-04-08 09:14:55

Building high availability of API gateways is crucial when constructing modern enterprise-level application architectures. As the core conduit for services and applications, API gateways play an indispensable role in handling massive requests, connecting complex services, and ensuring smooth data transmission.

This article delves into [API7 Enterprise](https://api7.ai/enterprise), an enterprise-level API management platform built on the open-source project [Apache APISIX](https://api7.ai/apisix), and explores how its data plane (API7 Gateway) ensures the stability and continuity of services through its internal high availability strategy during exceptional circumstances.

## Enterprise-level High Availability Architecture

In our previous discussions of [API7 enterprise-level high availability solutions](https://api7.ai/blog/api7-solution-for-robust-api-services), we've comprehensively understood how API7 Enterprise achieves high availability from the perspectives of internal component deployment and overall architectural system. Through the stateless design, API7 Enterprise can achieve rapid fault recovery and dynamic resource scheduling, ensuring high availability of services under various network and hardware abnormalities. This design not only optimizes resource utilization but also reduces system complexity, providing enterprises with a stable, reliable, and easily manageable API management platform.

![High availability of API7 Enterprise](https://static.apiseven.com/uploads/2024/04/08/CKH8C6Gx_high-availability.png)

## High Availability Strategies of API7 Enterprise

Building upon the excellent features of the open-source project [Apache APISIX](https://api7.ai/blog/why-is-apache-apisix-the-best-api-gateway), API7 Enterprise further enhances its high availability in enterprise-level applications. Especially when dealing with instances of API gateway interruption or the need for restart due to exceptional circumstances, API7 Gateway, the data plane component of API7 Enterprise adopts a series of innovative strategies to ensure service continuity and data consistency. These strategies are divided into three phases:

1. Configuration recovery at startup;

2. Full configuration synchronization and local storage;

3. Dynamic configuration changes and persistence.

These are designed to address the extreme circumstances of the data plane's inability to connect to the control plane due to significant uncertainties (such as DNS, network, control plane, etc.).

### Configuration Recovery at Startup

Considering that the connection to the control plane may be interrupted due to network anomalies or other unforeseen factors, API7 Gateway has designed a startup configuration recovery mechanism: when the gateway instance starts up, if the connection to the configuration center fails, it will automatically retrieve the latest configuration from local storage. This ensures that even in the case of restarting instances and the control plane unreachable, the gateway can use the previous configuration to start normally, thus avoiding service interruption.

In more extreme cases, you can change the instance's local configuration files, which can be used as API7 Gateway's startup configuration.

### Full Configuration Synchronization and Local Storage

API7 Gateway strengthens the configuration synchronization mechanism: after successfully connecting to the configuration center and startup, it fully synchronizes configuration information and stores this information in JSON format in the local file system. This mechanism ensures that even in the event of a subsequent runtime connection interruption with the configuration center, the gateway can rely on memory or local configuration to continue providing services.

### Dynamic Configuration Changes and Persistence

To cope with runtime configuration changes, API7 Gateway implements real-time monitoring and persistent storage of configuration updates. Whenever the control plane pushes new configuration updates, the gateway not only applies these changes in real time but also automatically updates the local storage configuration file. This ensures that the gateway can quickly restore to the latest configuration status when facing sudden restarts, minimizing service interruption time to the maximum extent.

## Designs for Handling Extreme Situations

API7 Gateway's design fully considers various extreme situations, including network isolation, control plane failures, and local resource limitations. By persistently storing configurations locally and optimizing startup and runtime configuration recovery logic, API7 Gateway strengthens its service capabilities in unstable environments. This design not only enhances the robustness of the API gateway but also provides enterprise users with a higher level of business continuity assurance.

## Conclusion

The high availability strategy of API7 Gateway is one of the core competitive advantages of API7 Enterprise as an enterprise-level API gateway solution. Through innovative configuration recovery mechanisms, full configuration synchronization, and local storage, as well as real-time application and persistence of dynamic configuration changes, API7 Gateway ensures service stability and continuity when facing exceptional circumstances such as control plane unavailability or instance restarts. The implementation of these strategies not only reduces the burden of operations and maintenance but also greatly improves the reliability and user experience of enterprise applications.

In the wave of digital transformation, the demand for [high availability](https://api7.ai/blog/enhance-high-availability-with-api-governance) of API management platforms by enterprises is increasing. With its advanced design and technological implementation, API7 Enterprise not only ensures service high availability but also opens up broader business possibilities for enterprises.