Dependent resources

Mon, 01 Jan 0001 00:00:00 +0000

Motivations and Goals

Most operators need to deal with secondary resources when trying to realize the desired state described by the primary resource they are in charge of. For example, the Kubernetes-native Deployment controller needs to manage ReplicaSet instances as part of a Deployment’s reconciliation process. In this instance, ReplicatSet is considered a secondary resource for the Deployment controller.

Controllers that deal with secondary resources typically need to perform the following steps, for each secondary resource:

Workflows

Mon, 01 Jan 0001 00:00:00 +0000

Overview

Kubernetes (k8s) does not have the notion of a resource “depending on” on another k8s resource, at least not in terms of the order in which these resources should be reconciled. Kubernetes operators typically need to reconcile resources in order because these resources’ state often depends on the state of other resources or cannot be processed until these other resources reach a given state or some condition holds true for them. Dealing with such scenarios are therefore rather common for operators and the purpose of the workflow feature of the Java Operator SDK (JOSDK) is to simplify supporting such cases in a declarative way. Workflows build on top of the dependent resources feature. While dependent resources focus on how a given secondary resource should be reconciled, workflows focus on orchestrating how these dependent resources should be reconciled.

Dependent resources and workflows on Java Operator SDK

Dependent resources

Motivations and Goals

Workflows

Overview