Convert docs to docsy

site/content/en/api-reference/kustomization/vars/_index.md

@@ -0,0 +1,85 @@
+---
+title: "vars"
+linkTitle: "vars"
+type: docs
+description: >
+    Substitute name references.
+---
+
+Vars are used to capture text from one resource's field
+and insert that text elsewhere - a reflection feature.
+
+For example, suppose one specifies the name of a k8s Service
+object in a container's command line, and the name of a
+k8s Secret object in a container's environment variable,
+so that the following would work:
+
+```yaml
+
+containers:
+  - image: myimage
+    command: ["start", "--host", "$(MY_SERVICE_NAME)"]
+    env:
+    - name: SECRET_TOKEN
+      value: $(SOME_SECRET_NAME)
+```
+
+To do so, add an entry to `vars:` as follows:
+
+```yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+vars:
+- name: SOME_SECRET_NAME
+  objref:
+    kind: Secret
+    name: my-secret
+    apiVersion: v1
+- name: MY_SERVICE_NAME
+  objref:
+    kind: Service
+    name: my-service
+    apiVersion: v1
+  fieldref:
+    fieldpath: metadata.name
+- name: ANOTHER_DEPLOYMENTS_POD_RESTART_POLICY
+  objref:
+    kind: Deployment
+    name: my-deployment
+    apiVersion: apps/v1
+  fieldref:
+    fieldpath: spec.template.spec.restartPolicy
+```
+
+A var is a tuple of variable name, object
+reference and field reference within that object.
+That's where the text is found.
+
+The field reference is optional; it defaults to
+`metadata.name`, a normal default, since kustomize
+is used to generate or modify the names of
+resources.
+
+At time of writing, only string type fields are
+supported.  No ints, bools, arrays etc.  It's not
+possible to, say, extract the name of the image in
+container number 2 of some pod template.
+
+A variable reference, i.e. the string '$(FOO)',
+can only be placed in particular fields of
+particular objects as specified by kustomize's
+configuration data.
+
+The default config data for vars is at [/api/konfig/builtinpluginconsts/varreference.go](/konfig/builtinpluginconsts/varreference.go)
+Long story short, the default targets are all
+container command args and env value fields.
+
+Vars should _not_ be used for inserting names in
+places where kustomize is already handling that
+job.  E.g., a Deployment may reference a ConfigMap
+by name, and if kustomize changes the name of a
+ConfigMap, it knows to change the name reference
+in the Deployment.
+
+