d0d289fb7c
Updated references from chaos-kubox to redhat-chaos. Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>
3.2 KiB
Litmus Scenarios
Kraken consumes Litmus under the hood for some scenarios
Official Litmus documentation and specifics of Litmus resources can be found here
Litmus Chaos Custom Resources
There are 3 custom resources that are created during each Litmus scenario. Below is a description of the resources:
- ChaosEngine: A resource to link a Kubernetes application or Kubernetes node to a ChaosExperiment. ChaosEngine is watched by Litmus' Chaos-Operator which then invokes Chaos-Experiments.
- ChaosExperiment: A resource to group the configuration parameters of a chaos experiment. ChaosExperiment CRs are created by the operator when experiments are invoked by ChaosEngine.
- ChaosResult : A resource to hold the results of a chaos-experiment. The Chaos-exporter reads the results and exports the metrics into a configured Prometheus server.
Understanding Litmus Scenarios
To run Litmus scenarios we need to apply 3 different resources/yaml files to our cluster.
-
Chaos experiments contain the actual chaos details of a scenario.
i. This is installed automatically by Kraken (does not need to be specified in kraken scenario configuration).
-
Service Account: should be created to allow chaosengine to run experiments in your application namespace. Usually it sets just enough permissions to a specific namespace to be able to run the experiment properly.
i. This can be defined using either a link to a yaml file or a downloaded file in the scenarios' folder.
-
Chaos Engine connects the application instance to a Chaos Experiment. This is where you define the specifics of your scenario; i.e.: the node or pod name you want to cause chaos within.
i. This is a downloaded yaml file in the scenarios' folder. A full list of scenarios can be found here
NOTE: By default, all chaos experiments will be installed based on the version you give in the config file.
Adding a new Litmus based scenario is as simple as adding references to 2 new yaml files (the Service Account and Chaos engine files for your scenario ) in the Kraken config.
Supported scenarios
The following are the start of scenarios for which a chaos scenario config exists today.
| Scenario | Description | Working |
|---|---|---|
| Node CPU Hog | Chaos scenario that hogs up the CPU on a defined node for a specific amount of time. | ✔️ |
| Node Memory Hog | Chaos scenario that hogs up the memory on a defined node for a specific amount of time. | ✔️ |
| Node IO Hog | Chaos scenario that hogs up the IO on a defined node for a specific amount of time. | ✔️ |