title: Kustomize how to replace only the host in Ingress configuration
body: <p>I've got this ingress.yaml base configuration:</p>
  <pre><code>apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    labels:
      sia: aza
      app: asap-ingress-internal
    name: asap-ingress-internal
    annotations:
      kubernetes.io/ingress.class: &quot;nginx-external&quot;
      nginx.ingress.kubernetes.io/use-regex: &quot;true&quot;
  spec:
    rules:
      - host: the-host-value
        http:
          paths:
            - path: /asap-srv-template/(.*)
              backend:
                serviceName: asap-srv-template
                servicePort: 8080
  </code></pre>
  <p>And want to replace the spoec.rules.host value only (and keep all http.paths as is.</p>
  <p>So I create a env-var.yaml like this :</p>
  <pre><code>apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    name: asap-ingress-internal
  spec:
    rules:
      - host: the.real.hostname
  </code></pre>
  <p>But the result is the following:</p>
  <pre><code>$ kustomize build
  apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    annotations:
      kubernetes.io/ingress.class: nginx-external
      nginx.ingress.kubernetes.io/use-regex: &quot;true&quot;
    labels:
      app: asap-ingress-internal
      env: dev
      sia: aza
    name: asap-ingress-internal
    namespace: aza-72461-dev
  spec:
    rules:
    - host: the.real.hostname
  </code></pre>
  <p>I have lost all http.paths configuration and I can't find out how to do.</p>
  <p>I tried with patches: or patchesStrategicMerge in kustomization.yaml but the result is always the same.</p>
  <p>Any help would be greatly appreciated</p>