Introduction to Chaos Mesh Workflow
When you use Chaos Mesh to simulate real system faults, continuous validation is always a need. You might want to build a series of faults on the Chaos Mesh platform, instead of performing individual Chaos injections.
To meet this need, Chaos Mesh provided Chaos Mesh Workflow, a built-in workflow engine. Using this engine, you can run different Chaos experiments in serial or parallel to simulate production-level errors.
Currently, Chaos Mesh Workflow supports the following features:
- Serial Orchestration
- Parallel Orchestration
- Customized tasks
- Conditional branch
Typical user scenarios:
- Use parallel orchestration to inject multiple NetworkChaos faults to simulate complex web environments.
- Use serial orchestration to perform health checks and use the conditional branch to determine whether to perform the remaining steps.
The design of Chaos Mesh Workflow is, to some extent, inspired by Argo Workflows. If you are familiar with Argo Workflows, you can also quickly get started with Chaos Mesh Workflow.
More workflow examples are available in the Chaos Mesh GitHub repository.
Create a workflow using a YAML file and
Similar to various types of Chaos objects, workflows also exist in a Kubernetes cluster as a CRD. You can create a Chaos Mesh workflow using
kubectl create -f <workflow.yaml>. The following command is an example of creating a workflow. Create a workflow using a local YAML file:
kubectl create -f <workflow.yaml>
Create a workflow using a YAML file from the network:
kubectl create -f https://raw.githubusercontent.com/chaos-mesh/chaos-mesh/master/examples/workflow/serial.yaml
A simple workflow YAML file is defined as follows. In this workflow,
PodChaos are injected:
- name: the-entry
- name: workflow-network-chaos
- name: workflow-pod-chaos-schedule
schedule: '@every 2s'
- name: workflow-stress-chaos
options: ['--cpu 1', '--timeout 600']
In the above YAML template, the
templates fields define the steps of the experiment. The
entry field defines the entry of the workflow when the workflow is being executed.
Each element in
templates represents a workflow step. For example:
templateType: Parallel means that the node type is parallel.
deadline: 240s means that all parallel experiments on this node are expected to be performed in 240 seconds; otherwise, the experiments time out.
children means the other template names to be executed in parallel.
templateType: PodChaos means that the node type is PodChaos experiments.
deadline: 40s means that the current Chaos experiment lasts for 40 seconds.
podChaos is the definition of the PodChaos experiment.
It is flexible to create a workflow using a YAML file and
kubectl. You can nest parallel or serial orchestrations to declare complex orchestrations, and even combine the orchestration with conditional branches to achieve a circular effect.
Workflow field description
|entry||string||Declares the entry of the workflow. Its value is a name of a template.||None||Yes|
|templates||Template||Declares the behavior of each step executable in the workflow. See Template field description for details.||None||Yes|
Template field description
|name||string||The name of the template, which needs to meet the DNS-1123 requirements.||None||Yes||any-name|
|type||string||Type of template. Value options are Task, Serial, Parallel, Suspend, Schedule, AWSChaos, DNSChaos, GCPChaos, HTTPChaos, IOChaos, JVMChaos, KernelChaos, NetworkChaos, PodChaos, StressChaos, and TimeChaos.||None||Yes||PodChaos|
|deadline||string||The duration of the template.||None||No||'5m30s'|
|children||string||Declares the subtasks under this template. You need to configure this field when the type is ||None||No||["any-chaos-1", "another-serial-2", "any-shcedue"]|
|task||Task||Configures the customized task. You need to configure this field when the type is ||None||No|
|conditionalBranches||ConditionalBranch||Configures the conditional branch which executes after customized task. You need to configure this field when the type is ||None||No|
|awsChaos||object||Configures AWSChaos. You need to configure this field when the type is ||None||No|
|dnsChaos||object||Configures DNSChaos. You need to configure this field when the type is ||None||No|
|gcpChaos||object||Configures GCPChaos. You need to configure this field when the type is ||None||No|
|httpChaos||object||Configures HTTPChaos. You need to configure this field when the type is ||None||No|
|ioChaos||object||Configure IOChaos. You need to configure this field when the type is ||None||No|
|jvmChaos||object||Configures JVMChaos. You need to configure this field when the type is ||None||No|
|kernelChaos||object||Configure KernelChaos. You need to configure this field when the type is ||None||No|
|networkChaos||object||Configures NetworkChaos. You need to configure this field when the type is ||None||No|
|podChaos||object||Configures PodChaosd. You need to configure this field when the type is ||None||No|
|stressChao||object||Configures StressChaos. You need to configure this field when the type is ||None||No|
|timeChaos||object||Configures TimeChaos. You need to configure this field when the type is ||None||No|
|schedule||object||Configures Schedule. You need to configure this field when the type is ||None||No|
When creating a Chaos with a duration in the workflow, you need to fill the duration in the outer
deadline field instead of using the
duration field in Chaos.
Task field description
|container||object||Defines a customized task container. See Container field description for details.||None||No|
|volumes||array||If you need to mount a volume in a customized task container, you need to declare the volume in this field. For the detailed definition of a volume, see the Kubernetes documentation - corev1.Volume.||None||No|
Conditional branch field description
|target||string||The name of the template to be executed by the current conditional branch.||None||Yes||another-chaos|
|expression||string||The type is a boolean expression. When a customized task is completed and the expression value is true, the current condition branch is executed. When this value is not set, the conditional branch will be executed directly after the customized task is completed.||None||No||exitCode == 0|
Currently, two context variables are provided in
exitCodemeans the exit code for a customized task.
stdoutindicates the standard output for a customized task.
More context variables will be added in later releases.
Refer to this document write
Container field description
The following table only lists the commonly used fields. For the definitions of more fields, see Kubernetes documentation - core1.Container.