docs(api/kustomizaion-file): migrate field sections

site/content/en/docs/Reference/API/Kustomization File/replicas.md

@@ -0,0 +1,90 @@
+---
+title: "replicas"
+linkTitle: "replicas"
+type: docs
+weight: 19
+description: >
+    Change the number of replicas for a resource.
+---
+
+Given this kubernetes Deployment fragment:
+
+```yaml
+kind: Deployment
+metadata:
+  name: deployment-name
+spec:
+  replicas: 3
+```
+
+one can change the number of replicas to 5
+by adding the following to your kustomization:
+
+```yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+replicas:
+- name: deployment-name
+  count: 5
+```
+
+This field accepts a list, so many resources can
+be modified at the same time.
+
+As this declaration does not take in a `kind:` nor a `group:`
+it will match any `group` and `kind` that has a matching name and
+that is one of:
+
+- `Deployment`
+- `ReplicationController`
+- `ReplicaSet`
+- `StatefulSet`
+
+For more complex use cases, revert to using a patch.
+
+## Example
+
+### Input File
+
+```yaml
+# deployment.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: the-deployment
+spec:
+  replicas: 5
+  template:
+    containers:
+      - name: the-container
+        image: registry/container:latest
+```
+
+```yaml
+# kustomization.yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+replicas:
+- name: the-deployment
+  count: 10
+
+resources:
+- deployment.yaml
+```
+
+### Output
+```yaml
+# deployment.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: the-deployment
+spec:
+  replicas: 10
+  template:
+    containers:
+      - name: the-container
+        image: registry/container:latest
+```