Project: Litmus (Observability and Analysis / Chaos Engineering)
File: spring-boot-latency.md

It can target random pods with a Spring Boot application and allows configuring the assaults to inject network latency to every nth request. This can be tuned via `CM_LEVEL` ENV. !!! tip "Scenario: Inject network latency to Spring Boot Application" ??? info "View the uses of the experiment" coming soon ??? info "Verify the prerequisites" <ul> <li> Ensure that Kubernetes Version > 1.16 </li> <li>Ensure that the Litmus Chaos Operator is running by executing <code>kubectl get pods</code> in operator namespace (typically, <code>litmus</code>).If not, install from <a href="https://v1-docs.litmuschaos.io/docs/getstarted/#install-litmus">here</a> </li> <li> Ensure that the <code> spring-boot-latency </code> experiment resource is available in the cluster by executing <code>kubectl get chaosexperiments</code> in the desired namespace. If not, install from <a href="https://hub.litmuschaos.io/api/chaos/master?file=faults/spring-boot/spring-boot-latency/fault.yaml">here</a></li> <li>Chaos Monkey Spring Boot dependency should be present in application. It can be enabled by two ways: <ol> <li>Add internal dependency inside the spring boot application <ol> <li>Add Chaos Monkey for Spring Boot as dependency for your project ```maven <dependency> <groupId>de.codecentric</groupId> <artifactId>chaos-monkey-spring-boot</artifactId> <version>2.6.1</version> </dependency> ``` </li> <li> Start your Spring Boot App with the chaos-monkey spring profile enabled ```bash java -jar your-app.jar --spring.profiles.active=chaos-monkey --chaos.monkey.enabled=true ``` </li> </ol> </li> <li> Add as external dependency <ol> <li>You can extend your existing application with the chaos-monkey and add it as an external dependency at startup, for this it is necessary to use the PropertiesLauncher of Spring Boot ```maven <dependency> <groupId>de.codecentric</groupId> <artifactId>chaos-monkey-spring-boot</artifactId> <classifier>jar-with-dependencies</classifier> <version>2.6.1</version> </dependency> ``` </li> <li>Start your Spring Boot application, add Chaos Monkey for Spring Boot JAR and properties ```bash java -cp your-app.jar -Dloader.path=chaos-monkey-spring-boot-2.6.1-jar-with-dependencies.jar org.springframework.boot.loader.PropertiesLauncher --spring.profiles.active=chaos-monkey --spring.config.location=file:./chaos-monkey.properties ``` </li> </ol> </li> </ol> </li> </ul> ??? info "View the default validations" Spring boot pods are healthy before and after chaos injection !!! tip "NOTE" If you are using this experiment as part of a litmus workflow scheduled constructed & executed from chaos-center, then you may be making use of the RBAC, which is pre-installed in the cluster as part of the agent setup. ??? note "View the Minimal RBAC permissions" ```yaml apiVersion: v1 kind: ServiceAccount metadata: name: spring-boot-latency-sa namespace: default labels: name: spring-boot-latency-sa app.kubernetes.io/part-of: litmus apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: spring-boot-latency-sa namespace: default labels: name: spring-boot-latency-sa app.kubernetes.io/part-of: litmus rules: apiGroups: [""] resources: ["pods"] verbs: ["create","delete","get","list","patch","update", "deletecollection"] apiGroups: [""] resources: ["events"] verbs: ["create","get","list","patch","update"] apiGroups: [""] resources: ["pods/log"] verbs: ["get","list","watch"] apiGroups: [""] resources: ["pods/exec"] verbs: ["get","list","create"] apiGroups: ["batch"] resources: ["jobs"] verbs: ["create","list","get","delete","deletecollection"] apiGroups: ["litmuschaos.io"] resources: ["chaosengines","chaosexperiments","chaosresults"] verbs: ["create","list","get","patch","update","delete"] apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: spring-boot-latency-sa namespace: default labels: name: spring-boot-latency-sa app.kubernetes.io/part-of: litmus roleRef: apiGroup:

kind: Role name: spring-boot-latency-sa subjects: kind: ServiceAccount name: spring-boot-latency-sa namespace: default ``` Use this sample RBAC manifest to create a chaosServiceAccount in the desired (app) namespace. This example consists of the minimum necessary role permissions to execute the experiment. ??? info "check the experiment tunables" <h2>Mandatory Fields</h2> <table> <tr> <th> Variables </th> <th> Description </th> <th> Notes </th> </tr> <tr> <td> CM_PORT </td> <td> It contains port of the spring boot application </td> <td> </td> </tr> <tr> <td> LATENCY </td> <td> It contains network latency to be injected(in ms)</td> <td> default value is 2000</td> </tr> </table> <h2>Optional Fields</h2> <table> <tr> <th> Variables </th> <th> Description </th> <th> Notes </th> </tr> <tr> <td> CM_LEVEL </td> <td> It contains number of requests are to be attacked, n value means nth request will be affected </td> <td> Defaults value: 1, it lies in [1,10000] range </td> </tr> <tr> <td> CMWATCHEDCUSTOM_SERVICES </td> <td> It limits watched packages/classes/methods, it contains comma seperated list of fully qualified packages(class and/or method names)</td> <td> ByDefault it is empty list, which means it target all services </td> </tr> <tr> <td> CM_WATCHERS </td> <td> It contains comma separated list of watchers from the following watchers list [controller, restController, service, repository, component, webClient] </td> <td> ByDefault it is <code> restController </code></td> </tr> <tr> <td> TOTALCHAOSDURATION </td> <td> The time duration for chaos injection (seconds) </td> <td> Defaults to 30 </td> </tr> <tr> <td> SEQUENCE </td> <td> It defines sequence of chaos execution for multiple target pods </td> <td> Default value: parallel. Supported: serial, parallel </td> </tr> <tr> <td> PODSAFFECTEDPERC </td> <td> The Percentage of total pods to target </td> <td> Defaults to 0% (corresponds to 1 replica) </td> </tr> <tr> <td> LIB </td> <td> The chaos lib used to inject the chaos </td> <td> Defaults to <code>litmus</code>. Supported <code>litmus</code> only </td> </tr> <tr> <td> RAMP_TIME </td> <td> Period to wait before and after injection of chaos in sec </td> <td> </td> </tr> </table> Refer the and to tune the common tunables for all experiments and spring-boot specific tunables. It tunes the spring-boot application port via `CM_PORT` ENV Use the following example to tune this: ```yaml apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: spring-boot-chaos namespace: default spec: appinfo: appns: 'default' applabel: 'app=spring-boot' appkind: 'deployment' engineState: 'active' chaosServiceAccount: spring-boot-latency-sa experiments: name: spring-boot-latency spec: components: env: name: CM_PORT value: '8080' ``` It contains network latency value in ms. It can be tunes via `LATENCY` ENV Use the following example to tune this: ```yaml apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: spring-boot-chaos namespace: default spec: appinfo: appns: 'default' applabel: 'app=spring-boot' appkind: 'deployment' engineState: 'active' chaosServiceAccount: spring-boot-latency-sa experiments: name: spring-boot-latency spec: components: env: name: LATENCY value: '2000' name: CM_PORT value: '8080' ```