Common tunables for pod experiments

It contains tunables, which are common for all pod-level experiments. These tunables can be provided at .spec.experiment[*].spec.components.env in chaosengine.

Target Specific Pods

It defines the comma-separated name of the target pods subjected to chaos. The target pods can be tuned via TARGET_PODS ENV.

Use the following example to tune this:

## it contains comma separated target pod names
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-delete-sa
  experiments:
  - name: pod-delete
    spec:
      components:
        env:
        ## comma separated target pod names
        - name: TARGET_PODS
          value: 'pod1,pod2'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Pod Affected Percentage

It defines the percentage of pods subjected to chaos with matching labels provided at .spec.appinfo.applabel inside chaosengine. It can be tuned with PODS_AFFECTED_PERC ENV. If PODS_AFFECTED_PERC is provided as empty or 0 then it will target a minimum of one pod.

Use the following example to tune this:

## it contains percentage of application pods to be targeted with matching labels or names in the application namespace
## supported for all pod-level experiment expect pod-autoscaler
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-delete-sa
  experiments:
  - name: pod-delete
    spec:
      components:
        env:
        # percentage of application pods
        - name: PODS_AFFECTED_PERC
          value: '100'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Target Specific Container

It defines the name of the targeted container subjected to chaos. It can be tuned via TARGET_CONTAINER ENV. If TARGET_CONTAINER is provided as empty then it will use the first container of the targeted pod.

Use the following example to tune this:

## name of the target container
## it will use first container as target container if TARGET_CONTAINER is provided as empty
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-delete-sa
  experiments:
  - name: pod-delete
    spec:
      components:
        env:
        # name of the target container
        - name: TARGET_CONTAINER
          value: 'nginx'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Default Application Health Check

It defines the default application status checks as a tunable. It is helpful for the scenarios where you don’t want to validate the application status as a mandatory check during pre & post chaos. It can be tuned via DEFAULT_APP_HEALTH_CHECK ENV. If DEFAULT_APP_HEALTH_CHECK is not provided by default it is set to true.

Use the following example to tune this:

## application status check as tunable
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-delete-sa
  experiments:
  - name: pod-delete
    spec:
      components:
        env:
        - name: DEFAULT_APP_HEALTH_CHECK
          value: 'false'

Node Label Filter For Selecting The Target Pods

It defines the target application pod selection from a specific node. It is helpful for the scenarios where you want to select the pods scheduled on specific nodes as chaos candidates considering the pod affected percentage. It can be tuned via NODE_LABEL ENV.

NOTE: This feature requires having node-level permission or clusterrole service account for filtering pods on a specific node.

APP_LABEL	TARGET_PODS	NODE_LABEL	SELECTED PODS
Provided	Provided	Provided	The target pods that are filtered from applabel and resides on node containing the given node label and also provided in TARGET_PODS env is selected
Provided	Not Provided	Provided	The pods that are filtered from applabel and resides on node containing the given node label is selected
Not Provided	Provided	Provided	The target pods are selected that resides on node with given node label
Not Provided	Not Provided	Provided	Invalid
Not Provided	Not Provided	Not Provided	Invalid

Use the following example to tune this:

## node label to filter target pods
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-delete-sa
  experiments:
  - name: pod-delete
    spec:
      components:
        env:
        - name: NODE_LABEL
          value: 'kubernetes.io/hostname=worker-01'