Validating Application Health

Inspecting the definition of health.yaml

Let’s take a look at yet another chaos experiment definition.

The output is as follows.

version: 1.0.0
title: What happens if we terminate an instance of the application?
description: If an instance of the application is terminated, a new instance should be created
tags:
- k8s
- pod
- deployment
steady-state-hypothesis:
  title: The app is healthy
  probes:
  - name: all-apps-are-healthy
    type: probe
    tolerance: true
    provider:
      type: python
      func: all_microservices_healthy
      module: chaosk8s.probes
      arguments:
        ns: go-demo-8
method:
- type: action
  name: terminate-app-pod
  provider:
    type: python
    module: chaosk8s.pod.actions
    func: terminate_pods
    arguments:
      label_selector: app=go-demo-8
      rand: true
      ns: go-demo-8

What do we have there?

The title asks what happens if we terminate an instance of an application?. The description says that if an instance of the application is terminated, a new instance should be created. Both should be self-explanatory and do not serve any practical purpose. They are informing us about the objectives of the experiment.

“So far, that definition looks almost the same as what we were doing in the previous section.” If that’s what you’re thinking, you’re right. Or, to be more precise, they are very similar.

The reason why we’re doing this again is that there is an easier and ...