Kubernetes 1.11 or later.
Running chaos on your application involves the following steps:
Apply the LitmusChaos Operator manifest:
kubectl apply -f https://litmuschaos.github.io/litmus/litmus-operator-v1.9.0.yaml
The above command installs all the CRDs, required service account configuration, and chaos-operator.
Note: Ensure that you have the right privileges to install the CRDs & setup cluster-wide RBAC policies (by default, the ChaosOperator watches for Chaos CRs across namespaces)
Before you start running a chaos experiment, verify if Litmus is installed correctly.
Verify your installation
- Verify if the ChaosOperator is running
kubectl get pods -n litmus
chaos-operator-ce-554d6c8f9f-slc8k 1/1 Running 0 6m41s
- Verify if chaos CRDs are installed
kubectl get crds | grep chaos
Verify if the chaos api resources are successfully created in the desired (application) namespace.
Note: Sometimes, it can take a few seconds for the resources to be available post the CRD installation
kubectl api-resources | grep chaos
chaosengines litmuschaos.io true ChaosEngine
chaosexperiments litmuschaos.io true ChaosExperiment
chaosresults litmuschaos.io true ChaosResult
In this guide, we shall describe the steps to inject pod-delete chaos on an nginx application already deployed in the nginx namespace. It is a mandatory requirement to ensure that the chaos custom resources (chaosexperiment and chaosengine) and the experiment specific serviceaccount are created in the same namespace (typically, the same as the namespace of the application under test (AUT), in this case nginx). This is done to ensure that the developers/users of the experiment isolate the chaos to their respective work-namespaces in shared environments.
In all subsequent steps, please follow these instructions by replacing the nginx namespace and labels with that of your application.
The ChaosOperator collects some usage metrics (operator installation count & experiment run count) via a google analytics hook. This is done in order to gather chaos trends that will help us to improve the project. However, if you would like to prevent the collection of the same or are operating in an airgapped environment, you can disable it using the procedure suggested here.
Install Chaos Experiments
Chaos experiments contain the actual chaos details. These experiments are installed on your cluster as Kubernetes CRs. The Chaos Experiments are grouped as Chaos Charts and are published on Chaos Hub.
The generic chaos experiments such as
pod-network-latency are available under Generic Chaos Chart.
This is the first chart you are recommended to install.
kubectl apply -f https://hub.litmuschaos.io/api/chaos/1.9.0?file=charts/generic/experiments.yaml -n nginx
Verify if the chaos experiments are installed.
kubectl get chaosexperiments -n nginx
Setup Service Account
A service account should be created to allow chaosengine to run experiments in your application namespace. Copy the following
rbac.yaml manifest and run
kubectl apply -f rbac.yaml to create one such account on the nginx namespace. This serviceaccount has just enough permissions needed to run the pod-delete chaos experiment.
- For rbac samples corresponding to other experiments such as, say, container-kill, please refer the respective experiment folder in the chaos-charts repository.
apiVersion: v1 kind: ServiceAccount metadata: name: pod-delete-sa namespace: nginx labels: name: pod-delete-sa apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: pod-delete-sa namespace: nginx labels: name: pod-delete-sa rules: - apiGroups: ["","litmuschaos.io","batch","apps"] resources: ["pods","deployments","pods/log","events","jobs","chaosengines","chaosexperiments","chaosresults"] verbs: ["create","list","get","patch","update","delete","deletecollection"] apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: pod-delete-sa namespace: nginx labels: name: pod-delete-sa roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: pod-delete-sa subjects: - kind: ServiceAccount name: pod-delete-sa namespace: nginx
Annotate your application
Your application has to be annotated with
litmuschaos.io/chaos="true". As a security measure, and also as a means
to reduce blast radius the ChaosOperator checks for this annotation before invoking chaos experiment(s) on the application.
nginx with the name of your deployment.
kubectl annotate deploy/nginx litmuschaos.io/chaos="true" -n nginx
ChaosEngine connects the application instance to a Chaos Experiment. Copy the following YAML snippet into a file called
chaosengine.yaml and update the values of
experiments as per your choice.
chaosServiceAccount to the name of service account created in above previous steps.
NOTE: To learn more about the various fields in the ChaosEngine spec and their supported values, refer to Constructing ChaosEngine
apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: nginx-chaos namespace: nginx spec: appinfo: appns: 'nginx' applabel: 'app=nginx' appkind: 'deployment' # It can be true/false annotationCheck: 'true' # It can be active/stop engineState: 'active' #ex. values: ns1:name=percona,ns2:run=nginx auxiliaryAppInfo: '' chaosServiceAccount: pod-delete-sa monitoring: false # It can be delete/retain jobCleanUpPolicy: 'delete' experiments: - name: pod-delete spec: components: env: # set chaos duration (in sec) as desired - name: TOTAL_CHAOS_DURATION value: '30' # set chaos interval (in sec) as desired - name: CHAOS_INTERVAL value: '10' # pod failures without '--force' & default terminationGracePeriodSeconds - name: FORCE value: 'false'
Override Default Chaos Experiments Variables
From LitmusChaos v1.1.0, the default environment variable values in chaosexperiments can be overridden by specifying
them in the chaosengine under
experiments.<experiment_name>.spec.components.env with the desired value. In the
example below, the
TOTAL_CHAOS_DURATION is being set to a desired value based on use-case.
... experiments: - name: pod-delete spec: components: env: - name: TOTAL_CHAOS_DURATION value: '30'
Apply the ChaosEngine manifest to trigger the experiment.
kubectl apply -f chaosengine.yaml
Observe Chaos results
Describe the ChaosResult CR to know the status of each experiment. The
status.verdict is set to
Awaited when the experiment is in progress, eventually changing to either
NOTE: ChaosResult CR name will be
kubectl describe chaosresult nginx-chaos-pod-delete -n nginx
Firstly, delete any active ChaosEngines on the cluster, followed by the deletion of the Operator manifest.
kubectl delete chaosengine --all -n <namespace>
kubectl delete -f https://litmuschaos.github.io/litmus/litmus-operator-v1.9.0.yaml
- Ensure that the chaosengine resources are deleted before removal of the chaos-operator deployment via operator manifest. Failure to do so can cause the uninstall operation to be "stuck". Refer to the these steps to resolve this condition and complete the uninstall.
For any issues experienced in running through the the aforementioned steps, refer to the Troubleshooting section.
More Chaos Experiments
- For more details on supported chaos experiments and the steps to run them, refer the respective Experiment docs.
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