Chaos experiment

Granular definition of chaos intent specified via image, library, necessary permissions, low-level chaos parameters (default values).

This section describes the fields in the chaos experiment and the possible values that can be set against the same.

Component specifications

Field	`.spec.definition.image`
Description	Flag to specify the image to run the ChaosExperiment
Type	Mandatory
Range	user-defined (type: string)
Default	n/a (refer Notes)
Notes	The `.spec.definition.image` allows the developers to specify their experiment images. Typically set to the Litmus `go-runner` or the `ansible-runner`. This feature of the experiment enables BYOC (BringYourOwnChaos), where developers can implement their own variants of a standard chaos experiment

Field	`.spec.definition.imagePullPolicy`
Description	Flag that helps the developers to specify imagePullPolicy for the ChaosExperiment
Type	Mandatory
Range	`IfNotPresent`, `Always` (type: string)
Default	`Always`
Notes	The `.spec.definition.imagePullPolicy` allows developers to specify the pull policy for ChaosExperiment image. Set to `Always` during debug/test

Image

It allows the developers to specify their experiment images. Typically set to the Litmus go-runner or the ansible-runner. This feature of the experiment enables BYOC (BringYourOwnChaos), where developers can implement their own variants of a standard chaos experiment. It can be tuned via image field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    # image of the chaosexperiment
    image: "litmuschaos/go-runner:latest"
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
      
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

ImagePullPolicy

It allows developers to specify the pull policy for ChaosExperiment image. Set to Always during debug/test. It can be tuned via imagePullPolicy field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    image: "litmuschaos/go-runner:latest"
    # imagePullPolicy of the chaosexperiment
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
      
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

Configuration Specification

Field	`.spec.definition.securityContext.podSecurityContext`
Description	Flag to specify security context for ChaosPod
Type	Optional
Range	user-defined (type:corev1.PodSecurityContext)
Default	n/a
Notes	The `.spec.definition.securityContext.podSecurityContext` allows the developers to specify the security context for the ChaosPod which applies to all containers inside the Pod.

Field	`.spec.definition.securityContext.containerSecurityContext.privileged`
Description	Flag to specify the security context for the ChaosExperiment pod
Type	Optional
Range	true, false (type:bool)
Default	n/a
Notes	The `.spec.definition.securityContext.containerSecurityContext.privileged` specify the securityContext params to the experiment container.

Field	`.spec.definition.hostFileVolumes`
Description	Flag to specify the host file volumes to the ChaosPod
Type	Optional
Range	user-defined (type:map[string]string)
Default	n/a
Notes	The `.spec.definition.hostFileVolumes` allows the developer to specify the host file volumes to the ChaosPod.

Field	`.spec.definition.hostPID`
Description	Flag to specify the host PID for the ChaosPod
Type	Optional
Range	true, false (type:bool)
Default	n/a
Notes	The `.spec.definition.hostPID` allows the developer to specify the host PID for the ChaosPod.

PodSecurityContext

It allows the developers to specify the security context for the ChaosPod which applies to all containers inside the Pod. It can be tuned via podSecurityContext field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    image: "litmuschaos/go-runner:latest"
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
    # it contains pod security context
    securityContext:
      podSecurityContext:
        allowPrivilegeEscalation: true
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

Container Security Context

It allows the developers to specify the security context for the container inside ChaosPod. It can be tuned via containerSecurityContext field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    image: "litmuschaos/go-runner:latest"
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
    # it contains container security context
    securityContext:
      containerSecurityContext:
        privileged: true
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

Host File Volumes

It allows the developer to specify the host file volumes to the ChaosPod. It can be tuned via hostFileVolumes field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    image: "litmuschaos/go-runner:latest"
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
    # it contains host file volumes
    hostFileVolumes:
      - name: socket file
        mountPath: "/run/containerd/containerd.sock"
        nodePath: "/run/containerd/containerd.sock"
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

Host PID

It allows the developer to specify the host PID for the ChaosPod. It can be tuned via hostPID field.

Use the following example to tune this:

apiVersion: litmuschaos.io/v1alpha1
description:
  message: |
    Deletes a pod belonging to a deployment/statefulset/daemonset
kind: ChaosExperiment
metadata:
  name: pod-delete
  labels:
    name: pod-delete
    app.kubernetes.io/part-of: litmus
    app.kubernetes.io/component: chaosexperiment
    app.kubernetes.io/version: latest
spec:
  definition:
    scope: Namespaced
    permissions:
      - apiGroups:
          - ""
          - "apps"
          - "apps.openshift.io"
          - "argoproj.io"
          - "batch"
          - "litmuschaos.io"
        resources:
          - "deployments"
          - "jobs"
          - "pods"
          - "pods/log"
          - "replicationcontrollers"
          - "deployments"
          - "statefulsets"
          - "daemonsets"
          - "replicasets"
          - "deploymentconfigs"
          - "rollouts"
          - "pods/exec"
          - "events"
          - "chaosengines"
          - "chaosexperiments"
          - "chaosresults"
        verbs:
          - "create"
          - "list"
          - "get"
          - "patch"
          - "update"
          - "delete"
          - "deletecollection"
    image: "litmuschaos/go-runner:latest"
    imagePullPolicy: Always
    args:
    - -c
    - ./experiments -name pod-delete
    command:
    - /bin/bash
    env:

    - name: TOTAL_CHAOS_DURATION
      value: '15'

    - name: RAMP_TIME
      value: ''

    - name: FORCE
      value: 'true'

    - name: CHAOS_INTERVAL
      value: '5'

    - name: PODS_AFFECTED_PERC
      value: ''

    - name: LIB
      value: 'litmus'    

    - name: TARGET_PODS
      value: ''

    - name: SEQUENCE
      value: 'parallel'
    # it allows hostPID
    hostPID: true
    labels:
      name: pod-delete
      app.kubernetes.io/part-of: litmus
      app.kubernetes.io/component: experiment-job
      app.kubernetes.io/version: latest

Component specifications​

Image​

ImagePullPolicy​

Configuration Specification​

PodSecurityContext​

Container Security Context​

Host File Volumes​

Host PID​

Component specifications

Image

ImagePullPolicy

Configuration Specification

PodSecurityContext

Container Security Context

Host File Volumes

Host PID