Kubernetes Strategic Merge Patch

External

• https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md
• https://github.com/kubernetes-sigs/kustomize/blob/master/docs/glossary.md#patchstrategicmerge

Internal

• kubectl kustomize
• kubectl apply
• kubectl edit
• kubectl patch

Overview

A strategic merge patch is a customized version of JSON patch and it looks like an incomplete YAML specification of a k8s resource.

The SMP includes TypeMeta fields to establish the group/version/kind/name of the resource to patch, then just enough remaining fields to step into a nested structure to specify a new field value, e.g. an image tag. By default, an SMP replaces values. This is usually the desired behavior when the target value is a simple string, but may not be desired when the target value is a list. To change this default behavior, add a directive. Recognized directives in YAML patches are:

• replace (the default)
• delete