Chaos Engineering in a Spring Boot Microservice

3 min readJan 1, 2020

Is your microservice ready for production ? Is your microservice fault-tolerant ? To answer those questions, all you have to do is break things on purpose and see how your microservice will react to it. Those experiments are what chaos engineering really is.

As defined by wikipedia :

Chaos Engineering is the discipline of experimenting on a system in order to build confidence in the system’s capability to withstand turbulent conditions in production.

Those planned experiments are designed to help us figure out the weakness of the system we are building/already built.

Benefits of chaos engineering

Controlled and planned chaos experiments
Preparing for unpredictable failure
Preparing engineers for failure
Improving SLA
Fortifying resilience of microservice architecture

Integrating chaos engineering into the DevOps toolchain contributes to the goal of continuous testing. Many companies such as Netflix, Amazon, Dropbox, Uber, Slack, … follow that discipline.

One of the tools that can help you to implement chaos engineering in a spring boot application is ChaosMonkey.

Chaos Monkey

Chaos monkey, a tool created by Netflix internally in 2010 and published in 2012, aims to help applications tolerate random instance failures. This tool has introduced some principles of chaos engineering into spring boot application.

Functionalities

Latency assault : adding random latency to REST endpoints
Exception assault : throwing random runtime exceptions
AppKiller assault : killing the app

How to configure Chaos Monkey in a spring boot application ?

Add the following dependency in your sprint boot application

<dependency>
   <groupId>de.codecentric</groupId>
   <artifactId>chaos-monkey-spring-boot</artifactId>
   <version>2.1.1</version>
</dependency>

Customise the chaos-monkey properties inside your application.properties file, inside your application.yml file. The following configuration will enable chaos monkey and will generate one of the assault with a frequency of 5 (1 out 5 calls) on each rest call.

chaos:
 monkey:
   enabled: true
 assaults:
   level: 5
 watcher:
   rest-controller: true

Start your application by specifying the spring profile as chaos-monkey

--spring.profiles.active=chaos-monkey

Once you run the microservice, you can check in the console to make sure that chaos monkey is ready to create chaos.

Adding random latency to the REST endpoints

With the following configuration, you enable latency to REST endpoint. In this case, each latency will vary from 1 to 5 seconds.

chaos:
  monkey:
    assaults:
      latency-active: true
      latency-range-end: 1000
      latency-range-start: 5000

Throwing random exceptions

With the following configurations, random runtime exceptions will be thrown.

chaos:
  monkey:
    assaults:
      exceptions-active: true

Killing the application

With the following configurations, the microservice will be destroyed.

chaos:
  monkey:
    assaults:
      kill-application-active: true

You can check the full documentation of the properties on the following link.

Thank you for reading my first post, hopefully it was helpful and gave you an idea on what chaos engineering is and how to implement it using chaos monkey in a spring boot microservice.

Stay tuned for my next posts. Feel free to comment down, if you have any question or If I missed something 😬.