Kubernetes Patterns, 2nd Edition

Chapter 2. Predictable Demands

The foundation of successful application deployment, management, and coexistence on a shared cloud environment is dependent on identifying and declaring the application resource requirements and runtime dependencies. This Predictable Demands pattern indicates how you should declare application requirements, whether they are hard runtime dependencies or resource requirements. Declaring your requirements is essential for Kubernetes to find the right place for your application within the cluster.

Problem

Kubernetes can manage applications written in different programming languages as long as the application can be run in a container. However, different languages have different resource requirements. Typically, a compiled language runs faster and often requires less memory compared to just-in-time runtimes or interpreted languages. Considering that many modern programming languages in the same category have similar resource requirements, from a resource consumption point of view, more important aspects are the domain, the business logic of an application, and the actual implementation details.

Besides resource requirements, application runtimes also have dependencies on platform-managed capabilities like data storage or application configuration.

Solution

Knowing the runtime requirements for a container is important mainly for two reasons. First, with all the runtime dependencies defined and resource demands envisaged, Kubernetes can make intelligent ...