Kubernetes is a powerful tool. It can help you manage complex applications and provide you with the ability to easily automate tasks involved in managing them. In this course, we will start exploring Kubernetes from a beginner's standpoint. We will discuss what Kubernetes is and what it does, and we will work with some of the basic functionality of Kubernetes hands-on. We will build a simple Kubernetes cluster. We will also deploy a sample microservice application to the cluster in order to explore how Kubernetes can help easily manage such applications.

A Practical Guide to Kubernetes

# Why to Monitor Health?

The [go-demo-2](https://github.com/vfarcic/k8s-specs/blob/master/pod/go-demo-2.yml) Docker image is designed to fail on the first sign of trouble. In cases like that, there is no need for any health checks. When things go wrong:
* The main process stops. 
* The container hosting the main process stops as well.
* Kubernetes restarts the failed container. 

However, not all services are designed to fail fast. Even those that are might still benefit from additional health checks. For example, a back-end API can be up and running but, due to a memory leak, serves requests much slower than expected. Such a situation might benefit from a health check that would verify whether the service responds within, for example, two seconds. 

# Kubernetes Probes
We can exploit Kubernetes **liveness and readiness probes** for that.
## Liveness Probe
`livenessProbe` can be used to confirm whether a container should be running. If the probe fails, Kubernetes will kill the container and apply restart policy which defaults to `Always`.
## Readiness Probe
 

We'll leave `readinessProbe` for [later](https://www.educative.io/collection/page/5376908829130752/4742963282313216/6332913870176256) since it is directly tied to `Services`. 

Instead, we'll explore `livenessProbe`. Both are defined in the same way so the experience with one of them can be easily applied to the other.

# Understanding the Updated Pod Definition
Let's take a look at an updated definition of the Pod we used thus far.

In this lesson, we will find out why to monitor the health of services and how to achieve this using Kubernetes Probes.

Monitoring Health

Why to Monitor Health?