Kubernetes PropertySource implementations

The most common approach to configuring your Spring Boot application is to create an application.properties or application.yaml or an application-profile.properties or application-profile.yaml file that contains key-value pairs that provide customization values to your application or Spring Boot starters. You can override these properties by specifying system properties or environment variables.

To enable this functionality you need to set the spring.config.import application configuration property to kubernetes: (escape with quotes when using yaml eg. "kubernetes:"):

spring:
  config:
    import: "kubernetes:"

Property source precedence

Kubernetes property sources loaded with spring.config.import follow Spring Boot’s Config Data precedence rules. Imported configuration has higher precedence than the configuration document that declares the import. For example, when the import is declared in application.yaml, a value from kubernetes: overrides the same value from that document.

When multiple locations are configured in spring.config.import, they are processed in the order in which they are declared. A later import has higher precedence than an earlier import. For example:

spring:
  config:
    import:
      - "optional:configserver:"
      - "kubernetes:"

In this example, Kubernetes configuration overrides Config Server configuration, and both override values from the configuration document that declares these imports. Reversing the two imports makes Config Server configuration override Kubernetes configuration.

Higher-precedence Spring Boot property sources, such as command-line arguments, Java system properties, and operating system environment variables, still override values loaded through spring.config.import.

If you would like to load Kubernetes PropertySources during the bootstrap phase like it worked prior to the 3.0.x release you can either add spring-cloud-starter-bootstrap to your application’s classpath or set spring.cloud.bootstrap.enabled=true as an environment variable.

When legacy bootstrap is used, bootstrap.yaml configures the bootstrap context. It does not control the relative precedence of the remote property sources located by that context. Kubernetes ConfigMap and Config Server property source locators both have order 0, so applications should not rely on a particular precedence between them. The Kubernetes Secret property source locator has order 1. Use spring.config.import when deterministic ordering between Kubernetes and Config Server configuration is required.

It is not supported to load properties during Bootstrap (using spring-cloud-starter-bootstrap or spring.cloud.bootstrap.enabled=true and load properties using spring.config.import. You must use one or the other method.

Section Summary