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Diff for: ‎docs/content/en/blog/_index.md

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---
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title: Blog
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menu: {main: {weight: 30}}
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menu: {main: {weight: 2}}
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---
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This is the **blog** section. It has two categories: News and Releases.

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title: Posts
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weight: 20
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weight: 220
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---

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title: Releases
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weight: 20
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weight: 230
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title: Community
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menu: {main: {weight: 40}}
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menu: {main: {weight: 3}}
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<!--add blocks of content here to add more sections to the community page -->

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title: Documentation
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linkTitle: Docs
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menu: {main: {weight: 20}}
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weight: 20
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menu: {main: {weight: 1}}
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weight: 1
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---
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Diff for: ‎docs/content/en/docs/contributing/_index.md

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title: Contributing To Java Operator SDK
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weight: 100
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weight: 110
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First of all, we'd like to thank you for considering contributing to the project! We really

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---
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title: Documentation
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weight: 40
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---

Diff for: ‎docs/content/en/docs/architecture/_index.md renamed to ‎docs/content/en/docs/documentation/architecture.md

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---
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title: Architecture and Internals
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weight: 90
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weight: 85
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---
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6-
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This document gives an overview of the internal structure and components of Java Operator SDK core,
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in order to make it easier for developers to understand and contribute to it. This document is
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not intended to be a comprehensive reference, rather an introduction to the core concepts and we

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---
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title: Configuring JOSDK
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layout: docs
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permalink: /docs/configuration
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title: Configurations
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weight: 55
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---
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# Configuration options
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The Java Operator SDK (JOSDK) provides several abstractions that work great out of the
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box. However, while we strive to cover the most common cases with the default behavior, we also
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recognize that that default behavior is not always what any given user might want for their
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configOverrider.withFinalizer("my-nifty-operator/finalizer").withLabelSelector("foo=bar"));
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```
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## Dynamically Changing Target Namespaces
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A controller can be configured to watch a specific set of namespaces in addition of the
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namespace in which it is currently deployed or the whole cluster. The framework supports
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dynamically changing the list of these namespaces while the operator is running.
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When a reconciler is registered, an instance of
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[`RegisteredController`](https://github.com/java-operator-sdk/java-operator-sdk/blob/ec37025a15046d8f409c77616110024bf32c3416/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/RegisteredController.java#L5)
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is returned, providing access to the methods allowing users to change watched namespaces as the
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operator is running.
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A typical scenario would probably involve extracting the list of target namespaces from a
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`ConfigMap` or some other input but this part is out of the scope of the framework since this is
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use-case specific. For example, reacting to changes to a `ConfigMap` would probably involve
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registering an associated `Informer` and then calling the `changeNamespaces` method on
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`RegisteredController`.
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```java
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public static void main(String[] args) {
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KubernetesClient client = new DefaultKubernetesClient();
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Operator operator = new Operator(client);
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RegisteredController registeredController = operator.register(new WebPageReconciler(client));
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operator.installShutdownHook();
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operator.start();
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// call registeredController further while operator is running
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}
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```
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If watched namespaces change for a controller, it might be desirable to propagate these changes to
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`InformerEventSources` associated with the controller. In order to express this,
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`InformerEventSource` implementations interested in following such changes need to be
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configured appropriately so that the `followControllerNamespaceChanges` method returns `true`:
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```java
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@ControllerConfiguration
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public class MyReconciler implements Reconciler<TestCustomResource> {
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@Override
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public Map<String, EventSource> prepareEventSources(
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EventSourceContext<ChangeNamespaceTestCustomResource> context) {
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InformerEventSource<ConfigMap, TestCustomResource> configMapES =
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new InformerEventSource<>(InformerEventSourceConfiguration.from(ConfigMap.class, TestCustomResource.class)
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.withNamespacesInheritedFromController(context)
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.build(), context);
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return EventSourceUtils.nameEventSources(configMapES);
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}
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}
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```
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As seen in the above code snippet, the informer will have the initial namespaces inherited from
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controller, but also will adjust the target namespaces if it changes for the controller.
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See also
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the [integration test](https://github.com/operator-framework/java-operator-sdk/tree/main/operator-framework/src/test/java/io/javaoperatorsdk/operator/baseapi/changenamespace)
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for this feature.
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## DependentResource-level configuration
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`DependentResource` implementations can implement the `DependentResourceConfigurator` interface
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`KubernetesDependentResourceConfig` instance, which is then passed to the `configureWith` method
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implementation.
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TODO: still subject to change / uniformization
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TODO
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## EventSource-level configuration
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---
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title: Dependent resources and workflows
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weight: 70
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---
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Dependent resources and workflows are features sometimes referenced as higher
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level abstractions. These two related concepts provides an abstraction
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over reconciliation of a single resource (Dependent resource) and the
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orchestration of such resources (Workflows).

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title: Dependent Resources
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title: Dependent resources
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weight: 75
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## Motivations and Goals

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title: Workflows
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weight: 80
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## Overview

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---
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title: Error handling and retries
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weight: 46
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---
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## Automatic Retries on Error
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JOSDK will schedule an automatic retry of the reconciliation whenever an exception is thrown by
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your `Reconciler`. The retry is behavior is configurable but a default implementation is provided
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covering most of the typical use-cases, see
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[GenericRetry](https://github.com/java-operator-sdk/java-operator-sdk/blob/master/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/retry/GenericRetry.java)
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.
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```java
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GenericRetry.defaultLimitedExponentialRetry()
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.setInitialInterval(5000)
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.setIntervalMultiplier(1.5D)
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.setMaxAttempts(5);
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```
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You can also configure the default retry behavior using the `@GradualRetry` annotation.
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It is possible to provide a custom implementation using the `retry` field of the
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`@ControllerConfiguration` annotation and specifying the class of your custom implementation.
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Note that this class will need to provide an accessible no-arg constructor for automated
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instantiation. Additionally, your implementation can be automatically configured from an
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annotation that you can provide by having your `Retry` implementation implement the
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`AnnotationConfigurable` interface, parameterized with your annotation type. See the
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`GenericRetry` implementation for more details.
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Information about the current retry state is accessible from
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the [Context](https://github.com/java-operator-sdk/java-operator-sdk/blob/master/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/Context.java)
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object. Of note, particularly interesting is the `isLastAttempt` method, which could allow your
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`Reconciler` to implement a different behavior based on this status, by setting an error message
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in your resource' status, for example, when attempting a last retry.
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Note, though, that reaching the retry limit won't prevent new events to be processed. New
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reconciliations will happen for new events as usual. However, if an error also occurs that
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would normally trigger a retry, the SDK won't schedule one at this point since the retry limit
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is already reached.
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A successful execution resets the retry state.
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### Setting Error Status After Last Retry Attempt
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In order to facilitate error reporting, `Reconciler` can implement the
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[ErrorStatusHandler](https://github.com/java-operator-sdk/java-operator-sdk/blob/main/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/ErrorStatusHandler.java)
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interface:
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```java
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public interface ErrorStatusHandler<P extends HasMetadata> {
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ErrorStatusUpdateControl<P> updateErrorStatus(P resource, Context<P> context, Exception e);
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}
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```
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The `updateErrorStatus` method is called in case an exception is thrown from the `Reconciler`. It is
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also called even if no retry policy is configured, just after the reconciler execution.
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`RetryInfo.getAttemptCount()` is zero after the first reconciliation attempt, since it is not a
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result of a retry (regardless of whether a retry policy is configured or not).
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`ErrorStatusUpdateControl` is used to tell the SDK what to do and how to perform the status
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update on the primary resource, always performed as a status sub-resource request. Note that
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this update request will also produce an event, and will result in a reconciliation if the
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controller is not generation aware.
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This feature is only available for the `reconcile` method of the `Reconciler` interface, since
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there should not be updates to resource that have been marked for deletion.
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Retry can be skipped in cases of unrecoverable errors:
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```java
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ErrorStatusUpdateControl.patchStatus(customResource).withNoRetry();
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```
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### Correctness and Automatic Retries
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While it is possible to deactivate automatic retries, this is not desirable, unless for very
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specific reasons. Errors naturally occur, whether it be transient network errors or conflicts
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when a given resource is handled by a `Reconciler` but is modified at the same time by a user in
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a different process. Automatic retries handle these cases nicely and will usually result in a
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successful reconciliation.
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## Retry and Rescheduling and Event Handling Common Behavior
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Retry, reschedule and standard event processing form a relatively complex system, each of these
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functionalities interacting with the others. In the following, we describe the interplay of
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these features:
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1. A successful execution resets a retry and the rescheduled executions which were present before
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the reconciliation. However, a new rescheduling can be instructed from the reconciliation
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outcome (`UpdateControl` or `DeleteControl`).
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For example, if a reconciliation had previously been re-scheduled after some amount of time, but an event triggered
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the reconciliation (or cleanup) in the mean time, the scheduled execution would be automatically cancelled, i.e.
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re-scheduling a reconciliation does not guarantee that one will occur exactly at that time, it simply guarantees that
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one reconciliation will occur at that time at the latest, triggering one if no event from the cluster triggered one.
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Of course, it's always possible to re-schedule a new reconciliation at the end of that "automatic" reconciliation.
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Similarly, if a retry was scheduled, any event from the cluster triggering a successful execution in the mean time
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would cancel the scheduled retry (because there's now no point in retrying something that already succeeded)
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2. In case an exception happened, a retry is initiated. However, if an event is received
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meanwhile, it will be reconciled instantly, and this execution won't count as a retry attempt.
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3. If the retry limit is reached (so no more automatic retry would happen), but a new event
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received, the reconciliation will still happen, but won't reset the retry, and will still be
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marked as the last attempt in the retry info. The point (1) still holds, but in case of an
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error, no retry will happen.
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The thing to keep in mind when it comes to retrying or rescheduling is that JOSDK tries to avoid unnecessary work. When
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you reschedule an operation, you instruct JOSDK to perform that operation at the latest by the end of the rescheduling
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delay. If something occurred on the cluster that triggers that particular operation (reconciliation or cleanup), then
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JOSDK considers that there's no point in attempting that operation again at the end of the specified delay since there
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is now no point to do so anymore. The same idea also applies to retries.

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