Kustomize is a standalone tool to customize Kubernetes objects through a kustomization file.
Since 1.14, Kubectl also supports the management of Kubernetes objects using a kustomization file. To view Resources found in a directory containing a kustomization file, run the following command:
kubectl kustomize <kustomization_directory> To apply those Resources, run kubectl apply with --kustomize or -k flag:
kubectl apply -k <kustomization_directory> Before you begin Install kubectl.
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.

a tool to configure and create Kubernetes objects on multiple environments