5 Running applications in Kubernetes

This chapter covers the operations side of Kubernetes: we will walk through how to maintain applications that are already running in Kubernetes. The previous chapter covered how to create pods, scheduling attributes, ConfigMaps, and Secrets. This chapter covers common approaches you will take on the exam to complete tasks such as providing additional resources for an application, scaling applications, providing a consistent endpoint for applications, and rolling out new versions of an application. For this chapter, we have a mix of two domains: Workloads and Scheduling and Cluster Architecture, Installation, and Configuration. This chapter, in combination with the previous chapter, is focused on achieving high availability and self-healing for applications running in Kubernetes while customizing applications and extending the Kubernetes API.

5.1 Orchestrating applications

5.1.1 Modifying running applications

5.1.2 Application maintenance

5.1.3 Application rollouts

5.1.4 Exposing Deployments

5.1.5 Autoscaling

5.2 Node maintenance

5.2.1 Cordon and drain nodes

5.2.2 Adding nodes to the cluster

5.3 Using Helm and Kustomize

5.3.1 Helm

5.3.2 Kustomize

5.4 Custom Resource Definitions and operators

5.4.1 Defining a CRD

5.4.2 Installing operators and CRDs

5.4.3 Utilizing operators

Summary