Trust

When you run your applications on Kubernetes there is a trust relationship between your application and the cluster. Your application trusts that Kubernetes will provide the necessary resources in a safe environment. Kubernetes must trust that your application will be running and responsive to requests routed to it without hoarding excessive amounts of CPU, memory, and I/O. The Kubernetes control plane component Kubectl manages the lifecycles of Pods. The Kubelet daemons are constantly asking questions of trust from the running applications:

• Are you alive?
• Are you initializing?
• Are you ready to work?

Your applications can expose probe endpoints as a way to set up a contractual trust between your application and the cluster manager of resources.

In this lab, you will learn how to:

    ☐ Write a Node.js microservice with endpoints for probes
    ☐ Scan for Pods with missing probes
    ☐ Write a Startup probe
    ☐ Write a Liveness probe
    ☐ Write a Readiness probe
    ☐ Call probes using HTTP, TCP, or exec calls