Configuration options #

The Java Operator SDK (JOSDK for short) provides several abstractions that work great out of the box. However, while we strive to cover the most common cases with the default behavior, we also recognize that that default behavior is not always what any given user might want for their operator. Numerous configuration options are therefore provided to help people tailor the framework to their needs.

Configuration options act at several levels, depending on which behavior you wish to act upon:

• Operator-level using ConfigurationService
• Reconciler-level using ControllerConfiguration
• DependentResouce-level using the DependentResourceConfigurator interface
• EventSource-level: some event sources, such as InformerEventSource, might need to be fine-tuned to properly identify which events will trigger the associated reconciler.

Operator-level configuration #

Configuration that impacts the whole operator is performed via the ConfigurationService class. An instance is provided by the ConfigurationServiceProvider.instance() method. This is the normal way for user-code to retrieve the current ConfigurationService instance. Sensible defaults are provided but you can change the default behavior by overriding the current configuration using ConfigurationServiceProvider.overrideCurrent method, providing a ConfigurationServiceOverrider Consumer that will apply the modifications you wish to perform on the configuration.

For instance, if you wish to not validate that the CRDs are present on your cluster when the operator starts and configure leader election, you would do something similar to:

ConfigurationServiceProvider.overrideCurrent(o -> o.checkingCRDAndValidateLocalModel(false)
        .withLeaderElectionConfiguration(new LeaderElectionConfiguration("bar", "barNS")));

Note that you can also obtain the same result by passing the ConfigurationServiceOverrider Consumer instance to the Operator constructor:

new Operator(o -> o.checkingCRDAndValidateLocalModel(false)
        .withLeaderElectionConfiguration(new LeaderElectionConfiguration("bar","barNS")));

Reconciler-level configuration #

While reconcilers are typically configured using the @ControllerConfiguration annotation, it is also possible to override the configuration at runtime, when the reconciler is registered with the operator instance, either by passing it a completely new ControllerConfiguration instance or by preferably overriding some aspects of the current configuration using a ControllerConfigurationOverrider Consumer:

Operator operator;
Reconciler reconciler;
...
operator.register(reconciler, configOverrider ->
        configOverrider.withFinalizer("my-nifty-operator/finalizer").withLabelSelector("foo=bar"));

DependentResource-level configuration #

DependentResource implementations can implement the DependentResourceConfigurator interface to pass information to the implementation. For example, the SDK provides specific support for the KubernetesDependentResource, which can be configured via the @KubernetesDependent annotation. This annotation is, in turn, converted into a KubernetesDependentResourceConfig instance, which is then passed to the configureWith method implementation.

TODO: still subject to change / uniformization

EventSource-level configuration #

TODO