Placeholders on Krkn

Adding scenarios via plugin api

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

Scenario Plugin API:

This API enables seamless integration of Scenario Plugins for Krkn. Plugins are automatically detected and loaded by the plugin loader, provided they extend the AbstractPluginScenario abstract class, implement the required methods, and adhere to the specified naming conventions.

Plugin folder:

The plugin loader automatically loads plugins found in the krkn/scenario_plugins directory, relative to the Krkn root folder. Each plugin must reside in its own directory and can consist of one or more Python files. The entry point for each plugin is a Python class that extends the AbstractPluginScenario abstract class and implements its required methods.

Getting Started

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

Getting Started with Krkn-AI

This documentation details how to deploy a sample microservice application on Kubernetes Cluster and run Krkn-AI test.

Prerequisites

Follow this guide to install Krkn-AI CLI.
Krkn-AI uses Thanos Querier to fetch SLO metrics by PromQL. You can easily install it by setting up prometheus-operator in your cluster.

Deploy Sample Microservice

For demonstration purpose, we will deploy a sample microservice called robot-shop on the cluster:

Running a Chaos Scenario with Krkn

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Getting Started Running Chaos Scenarios

Config

Instructions on how to setup the config and all the available options supported can be found at Config.

In all the examples below you’ll replace the scenario_type with the scenario plugin type that can be found in the second column here

Running a Single Scenario

To run a single scenario, you’ll edit the krkn config file and only have 1 item in the list of chaos_scenarios

Setting Up Disconnected Enviornment

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Getting Started Running Chaos Scenarios in a Disconnected Enviornment

Mirror following images on the bastion host

quay.io/krkn-chaos/krkn-hub:node-scenarios-bm - Master/worker node disruptions on baremetal
quay.io/krkn-chaos/krkn-hub:network-chaos - Network disruptions/traffic shaping
quay.io/krkn-chaos/krkn-hub:pod-scenarios - Pod level disruptions and evaluating recovery time/availability
quay.io/krkn-chaos/krkn-hub:syn-flood - Generates substantial amount of traffic/half open connections targeting a service
quay.io/krkn-chaos/krkn-hub:node-cpu-hog - Hogs CPU on the target nodes
quay.io/krkn-chaos/krkn-hub:node-io-hog - Hogs IO on the target nodes
quay.io/krkn-chaos/krkn-hub:node-memory-hog - Hogs memory on the target nodes
quay.io/krkn-chaos/krkn-hub:pvc-scenarios - Fills up a given PersistentVolumeClaim
quay.io/krkn-chaos/krkn-hub:service-hijacking - Simulates fake HTTP response for a service
quay.io/krkn-chaos/krkn-hub:power-outages - Shuts down the cluster and turns it back on
quay.io/krkn-chaos/krkn-hub:container-scenarios - Kills a container via provided kill signal
quay.io/krkn-chaos/krkn-hub:application-outages - Isolates application Ingress/Egress traffic
quay.io/krkn-chaos/krkn-hub:time-scenarios - Tweaks time/date on the nodes
quay.io/krkn-chaos/krkn-hub:pod-network-chaos - Introduces network chaos at pod level
quay.io/krkn-chaos/krkn-hub:node-network-filter - Node ip traffic filtering
quay.io/krkn-chaos/krkn-hub:pod-network-filter - DNS, internal/external service outages

Will also need these mirrored images inside the cluster

Network disruptions - quay.io/krkn-chaos/krkn:tools
Hog scenarios ( CPU, Memory and IO ) - quay.io/krkn-chaos/krkn-hog
SYN flood - quay.io/krkn-chaos/krkn-syn-flood:latest
Pod network filter scenarios - quay.io/krkn-chaos/krkn-network-chaos:latest
Service hijacking scenarios - quay.io/krkn-chaos/krkn-service-hijacking:v0.1.3

How to Mirror

The strategy is simple:

Adding New Scenario to Krknctl

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Adding a New Scenario to Krknctl

For krknctl to find the parameters of the scenario it uses a krknctl input json file. Once this file is added to krkn-hub, krknctl will be able to find it along with the details of how to run the scenario.

Add KrknCtl Input Json

This file adds every environment variable that is set up for krkn-hub to be defined as a flag to the krknctl cli command. There are a number of different type of variables that you can use, each with their own required fields. See below for an example of the different variable types

Git Help For Contributions

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How to contribute

Contributions are always appreciated.

How to:

Pull request

In order to submit a change or a PR, please fork the project and follow instructions:

$ git clone http://github.com/<me>/krkn-hub
$ cd krkn-hub
$ git checkout -b <branch_name>
$ <make change>
$ git add <changes>
$ git commit -a
$ <insert good message>
$ git push

Squash Commits

If there are multiple commits, please rebase/squash multiple commits before creating the PR by following:

Getting Started with Running Scenarios

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

Quick Start with krknctl (Recommended)

Recommended Approach

krknctl is the recommended and easiest way to run krkn scenarios. It provides command auto-completion, input validation, and abstracts the complexities of the container environment so you can focus on chaos engineering.

Why krknctl?

krknctl is a dedicated CLI tool that streamlines running chaos scenarios by providing:

Command auto-completion - Quick access to all available commands
Input validation - Catch errors before they happen
Scenario descriptions - Built-in documentation and instructions
Simple workflow - No need to manage config files or containers

Get Started in 3 Steps:

Install krknctl - Follow the installation guide
Explore features - Learn about krknctl usage and how to execute chaos scenarios
Run scenarios - Check out each scenario’s documentation for krknctl examples

Alternative Methods

The following alternative methods are available for advanced use cases:

Testing your changes

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

This page gives details about how you can get a kind cluster configured to be able to run on krkn-lib (the lowest level of krkn-chaos repos) up through krknctl (our easiest way to run and highest level repo)

Configure Kind Testing Environment

Install kind
Create cluster using kind-config.yml under krkn-lib base folder

Cerberus

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

Cerberus

Guardian of Kubernetes and OpenShift Clusters

Cerberus watches the Kubernetes/OpenShift clusters for dead nodes, system component failures/health and exposes a go or no-go signal which can be consumed by other workload generators or applications in the cluster and act accordingly.

Workflow

Installation

Instructions on how to setup, configure and run Cerberus can be found at Installation.

Developers Guide

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This document describes how to develop and add to Krkn. Before you start, it is recommended that you read the following documents first:

Be sure to properly install Krkn. Then you can start to develop krkn. The following documents will help you get started:

Add k8s functionality to krkn-lib
Add a New Chaos Scenario using Plugin API: Adding a new scenario into krkn
Add a Health Check Plugin: Monitor services during chaos using the health check plugin system
Test your changes

NOTE: All base kubernetes functionality should be added into krkn-lib and called from krkn