Stages Configuration #

This document walks you through how to configure the Stages of Lifecycle.

What is a Stage? #

The Stage API is a kwok Configuration that allows users to define and simulate different stages in the lifecycle of Kubernetes resources, such as nodes and pods. Each Stage resource specifies a resourceRef field that identifies the type of resource that the stage applies to, and a selector field that determines when the stage should be executed.

A Stage resource has the following fields:

kind: Stage
  name: <string>
    apiGroup: <string>
    kind: <string>
      <string>: <string>
      <string>: <string>
    - key: <expressions-string>
      operator: <string>
      - <string>
    durationMilliseconds: <int>
      expressionFrom: <expressions-string>
    jitterDurationMilliseconds: <int>
      expressionFrom: <expressions-string>
    statusTemplate: <string>
      - value: <string>
      - value: <string>
      empty: <bool>
    delete: <bool>
  immediateNextStage: <bool>

By setting the selector and next fields in the spec section of a Stage resource, users can specify the conditions that need to be met for the stage to be applied, and the changes that will be made to the resource when the stage is applied. The next field allows users to define the new state of the resource using the statusTemplate field, modify the finalizers of the resource, and even delete the resource.

Additionally, the delay field in a Stage resource allows users to specify a delay before the stage is applied, and introduce jitter to the delay to specify the latest delay time to make the simulation more realistic. This can be useful for simulating real-world scenarios where events do not always happen at the same time.

By configuring the delay, selector, and next fields in a Stage, you can control when and how the stage is applied, providing a flexible and scalable way to simulate real-world scenarios in your Kubernetes cluster. This allows you to create complex and realistic simulations for testing, validation, and experimentation, and gain insights into the behavior and performance of your applications and infrastructure.

Expressions string #

The <expressions-string> is provided by the Go Implementation of JQ Expressions

Examples #

Node Stages #

This example shows how to configure the simplest and fastest stages of Node resource, which is also the default Node stages for kwok.

Default Node Stages

Pod Stages #

This example shows how to configure the simplest and fastest stages of Pod resource, which is also the default Pod stages for kwok.

Default Pod Stages


Pod Stages that simulate real behavior as closely as possible #

General Pod Stages