Be Prepared for the Worst Case: How to Implement Failover

Imagine you’ve built an ideal application on SAP Cloud Platform. It works the way it’s supposed to, fulfills its duties, and satisfies your users – until the worst case occurs: Due to an unexpected outage of the data center it’s deployed in, your app is temporarily unavailable. This does not only annoy your customers but potentially also costs you a lot of money: An application is only valuable as long as it’s accessible.

To avoid this worst-case scenario and guarantee your app’s high availability, make sure to invest in reliable emergency strategies – ideally already during your development process. One of the approaches you can apply, for example, is failover, which is the automated switching from one server, network, or system to a redundant other. The traffic that usually goes to your primary data center is thereby redirected to the secondary one, which then takes over the tasks as long as necessary. That way, you can maintain both functionality and availability.

To help you implement this principle for the development of SAPUI5 and HTML5 applications without data persistence or any kind of in-memory caching on SAP Cloud Platform, we’ve enhanced the SAP Cloud Platform Planning and Lifecycle-Management Guide by adding two chapters on Planning Failover on SAP Cloud Platform and Implementing Failover. In these sections, we use a straightforward example to describe how to deploy your application in two data centers in parallel, keep your application’s versions in primary and secondary data centers in sync, define when the failover process is triggered, and decide on the failback. Have a look!