Besides the interest in cloud technology there is a lot of interest in the term cloud native which describes applications that, besides following the 12-factors, have a strong relationship to cloud platforms. Cloud native and 12-factor applications are not synonymous; rather than cloud native includes the 12-factors, among other things.

Cloud native applications are designed to run on cloud PaaS offerings with all their benefits and challenges, embrace container technology and elastic scalability. They are built with the claim to provide modern, scalable, stateless and resilient applications, manageable within modern orchestration environments. Unlike the term native suggests, applications that follow this approach do not necessarily have to be built as green-field projects that support cloud technology from day one.

Important aspects for cloud native applications beyond the 12-factors are monitoring and application health concerns, which can be summarized as telemetry. Telemetry for enterprise applications include responsiveness, monitoring, domain-specific insights, health checks, and debugging. As we have seen previously, container orchestration supports us at least with the last two concerns: health checks and debugging. Running applications are probed whether they are still alive and healthy. Debugging and troubleshooting is possible by evaluating the log event streams, connecting into the running containers or executing processes.

Application monitoring need to be exposed by the running container. This requires a bit more effort from software developers. Domain-specific metrics need to be defined by the business experts first. It depends which metrics are interesting to business departments and will be exposed by the application. Technical metrics are gathered from the running application as well. Chapter 9, Monitoring, Performance, and Logging covers the topic of monitoring in regard to modern environments.

Another aspect that the 12-factors don't include are APIs and security thereof. SaaS applications communicate via exposed APIs that have to be made known to other teams of developers. The nature and structure of web services needs to be documented and agreed upon during development. This is especially the case when HTTP APIs don't implement Hypermedia. The applications need to know the nature and structure of exchanged information - ideally as early as possible in the development process. This also covers authentication and authorization. Application developers should be aware of security mechanisms they need to address before communicating to other services. In general it is not advisable to only think of security aspects after development. Chapter 10, Security covers this topic concerning cloud environments and integration into Java EE applications.

In order to build an umbrella for all technologies that embrace cloud platforms, the Cloud Native Computing Foundation was formed by several software vendors. It is part of the Linux Foundation, representing an foundation for cloud native Open Source Software. It contains technology that orchestrates, manages, monitors, traces or in some other way supports containerized microservices running in modern environments. As of writing this book, examples for technology projects being part of the Cloud Native Computing Foundation are Kubernetes, Prometheus, OpenTracing, or containerd.