Certified Kubernetes Administrator (CKA) Study Guide

Chapter 3. Workloads

When we talk about workloads in Kubernetes, we mean the API resource types that run an application. Those API resource types include a Deployment, ReplicaSet, StatefulSet, DaemonSet, Job, CronJob, and of course the Pod. The curriculum of the CKA is very specific about the types of workload you need to be familiar with. The exam will include only the Deployment, ReplicaSet, and Pod. You will need to understand replication and rollout features managed by a Deployment and understand the API primitives for injecting configuration data into a Pod.

Note

This chapter will use the concept of a volume. Take a look through Chapter 6 for more information if you’re not familiar with Kubernetes’ persistent storage options.

At a high level, this chapter covers the following concepts:

• A basic understanding of Deployments

• Deployment rollout and rollback functionality

• Manual and automatic scaling of the replicas controlled by a ReplicaSet

• ConfigMap and Secret

Managing Workloads with Deployments

In Kubernetes, a workload is executed in a Pod. There are various API resources that manage one or many Pods. In this section, we’ll concentrate on the API resources Deployment and ReplicaSet, which are most relevant to the exam. Moreover, we’ll briefly touch on the StatefulSet, which manages workloads that hold state.

Understanding Deployments

The central API resource for running an application in a container is the Pod. Using a single instance of a Pod to operate an application ...