add examples/istio-v1.0.2/patches.yml to show how ytt can be used wit…

…h kapp

examples/istio-v1.0.2/README.md

@@ -1,3 +1,6 @@
 # Istio
 
 Downloaded from: https://github.com/knative/serving/releases/tag/v0.2.1
+
+- `config.yml` can be used to get rid cluster changes
+- `patches.yml` can be used with `ytt` to get rid of helm specific and/or template inaccuracies

examples/istio-v1.0.2/config.yml

@@ -3,7 +3,7 @@ apiVersion: kapp.k14s.io/v1alpha1
 kind: Config
 
 rebaseRules:
-# It seems that caBundle is automatically populated
+#! It seems that caBundle is automatically populated
 - path: [webhooks, {allIndexes: true}, clientConfig, caBundle]
   merge: copy
   sources: [new, existing]

examples/istio-v1.0.2/patches.yml

@@ -0,0 +1,47 @@
+#@ load("@ytt:overlay", "overlay")
+
+#! annotations should be a map
+#@overlay/match by=overlay.subset({"kind": "Service", "metadata":{"name": "istio-egressgateway"}})
+---
+metadata:
+  #@overlay/remove
+  annotations:
+
+#! annotations should be a map
+#@overlay/match by=overlay.subset({"kind": "Service", "metadata":{"name": "istio-ingressgateway"}})
+---
+metadata:
+  #@overlay/remove
+  annotations:
+
+#@overlay/match by=overlay.subset({"kind": "MutatingWebhookConfiguration"})
+---
+metadata:
+  #! MWC is cluster-wide config
+  #@overlay/remove
+  namespace:
+webhooks:
+#@overlay/match by="name"
+- name: sidecar-injector.istio.io
+  clientConfig:
+    #! caBundle is populated by the cluster
+    #@overlay/remove
+    caBundle:
+
+#@overlay/match by=overlay.subset({"kind": "Deployment", "metadata":{"name": "istio-pilot"}})
+---
+spec:
+  template:
+    spec:
+      containers:
+      #@overlay/match by="name"
+      - name: discovery
+        resources:
+          requests:
+            #! Kubernetes changes 2048Mi to 2Gi
+            memory: 2Gi
+
+#! Delete all post-delete hooks as kapp does not run them
+#@overlay/match by=overlay.subset({"metadata":{"annotations": {"helm.sh/hook": "post-delete"}}}),expects="1+"
+#@overlay/remove
+---