litmus-docs/website/versioned_docs/version-1.0.0/getstarted.md

id	title	sidebar_label	original_id
getstarted	Getting Started with Litmus	Introduction	getstarted

---

Pre-requisites

Kubernetes 1.11 or later.

Getting Started

Running chaos on your application involves the following steps:

Install Litmus

Install Chaos Experiments

Setup Service Account

Annotate your application

Prepare ChaosEngine

Run Chaos

Observe chaos results

---

Install Litmus

kubectl apply -f https://litmuschaos.github.io/pages/litmus-operator-v1.0.0.yaml

The above command install all the CRDs, required service account configuration, and chaos-operator. Before you start running a chaos experiment, verify if your Litmus is installed correctly.

Verify your installation

• Verify if the chaos operator is running

kubectl get pods -n litmus

Expected output:

chaos-operator-ce-554d6c8f9f-slc8k 1/1 Running 0 6m41s

• Verify if chaos CRDs are installed

kubectl get crds | grep chaos

Expected output:

chaosengines.litmuschaos.io 2019-10-02T08:45:25Z

chaosexperiments.litmuschaos.io 2019-10-02T08:45:26Z

chaosresults.litmuschaos.io 2019-10-02T08:45:26Z

• 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

Expected output:

chaosengines litmuschaos.io true ChaosEngine

chaosexperiments litmuschaos.io true ChaosExperiment

chaosresults litmuschaos.io true ChaosResult

NOTE: In this guide, we shall describe the steps to inject chaos on an application deployed in the default namespace.

Install Chaos Experiments

Chaos experiments contain the actual chaos details. These experiments are installed on your cluster as Kubernetes CRs (Custom Resources). The Chaos Experiments are grouped as Chaos Charts and are published on ChaosHub.

The generic chaos experiments such as pod-kill, container-kill, network-delay are available under Generic Chaos Chart. This is the first chart you install. You can later install application specific chaos charts for running application oriented chaos.

kubectl apply -f https://hub.litmuschaos.io/api/chaos?file=charts/generic/experiments.yaml

Verify if the chaos experiments are installed.

kubectl get chaosexperiments

Setup Service Account

A Service Account should be created to allow chaosengine to run experiments in your application namespace. Copy the following into rbac.yaml and run kubectl apply -f rbac.yaml to create one such account on your default namespace. You can change the service account name and namespace as needed.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nginx-sa
  namespace: default
  labels:
    name: nginx-sa
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: nginx-sa
  namespace: default
  labels:
    name: nginx-sa
rules:
  - apiGroups: ['', 'litmuschaos.io', 'batch', 'apps']
    resources: ['pods', 'jobs', 'daemonsets', 'pods/exec', 'chaosengines', 'chaosexperiments', 'chaosresults']
    verbs: ['create', 'list', 'get', 'patch', 'update', 'delete']
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: nginx-sa
  namespace: default
  labels:
    name: nginx-sa
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: nginx-sa
subjects:
  - kind: ServiceAccount
    name: nginx-sa
    namespace: default

Annotate your application

Your application has to be annotated with litmuschaos.io/chaos="true". As a security measure, Chaos Operator checks for this annotation on the application before invoking chaos experiment(s) on the application. Replace nginx with the name of your deployment.

kubectl annotate deploy/nginx litmuschaos.io/chaos="true"

Prepare ChaosEngine

ChaosEngine connects application to the Chaos Experiment. Copy the following YAML snippet into a file called chaosengine.yaml and update the values of applabel , appns, appkind and experiments as per your choice. Toggle monitoring between true/false, to allow the chaos-exporter to fetch experiment related metrics. Change the chaosServiceAccount to the name of Service Account created in above step, if applicable.

# chaosengine.yaml
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
  namespace: default
spec:
  # It can be app/infra
  chaosType: 'app'
  #ex. values: ns1:name=percona,ns2:run=nginx
  auxiliaryAppInfo: ''
  components:
    runner:
      image: 'litmuschaos/chaos-executor:1.0.0'
      type: 'go'
  # It can be delete/retain
  jobCleanUpPolicy: 'delete'
  monitoring: false
  appinfo:
    appns: 'default'
    # FYI, To see app label, apply kubectl get pods --show-labels
    applabel: 'app=nginx'
    appkind: 'deployment'
  chaosServiceAccount: nginx-sa
  experiments:
    - name: container-kill
      spec:
        components:
          - name: TARGET_CONTAINER
            value: 'nginx'

Override Default Chaos Experiments Variables

After LitmusChaos v0.7.0, to override the default environment variables in chaosExperiments, add the entry of those variable with the same name under experiments.<experiment_name>.spec.components with the overriding value.

...
experiments:
    - name: container-kill
      spec:
        components:
        - name: TARGET_CONTAINER
          value: nginx

Run Chaos

kubectl apply -f chaosengine.yaml

NOTE: It is recommended to create Application, ChaosEngine, ChaosExperiment and ServiceAccount in the same namespace for smooth execution of experiments.

Observe Chaos results

Describe the ChaosResult CR to know the status of each experiment. The spec.verdict is set to Running when the experiment is in progress, eventually changing to either pass or fail.

NOTE: ChaosResult CR name will be {"<chaos-engine-name>-<chaos-experiment-name>"}

kubectl describe chaosresult engine-nginx-container-kill

Uninstallation

You can uninstall Litmus by deleting the namespace.

kubectl delete -f https://litmuschaos.github.io/pages/litmus-operator-v1.0.0.yaml

More Chaos Experiments

• For more details on supported chaos experiments and the steps to run them, refer to chaoshub section.

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