Using Kubectl's new Kustomize support for per-environment deployment of cert-manager resources

Introduction Kustomize is an increasingly popular tool for generating Kubernetes manifests, and is now included with Kubectl 1.14. Rather than using templates Kustomize works by applying modifications to already valid manifests. Using this pattern, it provides various features including resource namespacing, modification of metadata, and generation of Kubernetes Secrets. To start using Kustomize you need one or more Kubernetes manifests and a kustomization.yaml file. The kustomization.yaml file is itself a manifest, which specifies a list of resources, patches to apply, and various other options.