Add a helper function to customize K8s addon yamls and use it to customize Calico addons on GKE.

cluster/gce/gci/configure-helper.sh

@@ -2286,6 +2286,23 @@ EOF
   fi
 }
 
+# A helper function to set up a custom yaml for a k8s addon.
+#
+# $1: addon category under /etc/kubernetes
+# $2: manifest source dir
+# $3: manifest file
+# $4: custom yaml
+function setup-addon-custom-yaml {
+  local -r manifest_path="/etc/kubernetes/$1/$2/$3"
+  local -r custom_yaml="$4"
+  if [ -n "${custom_yaml:-}" ]; then
+    # Replace with custom manifest.
+    cat > "${manifest_path}" <<EOF
+    $custom_yaml
+EOF
+  fi
+}
+
 # Prepares the manifests of k8s addons, and starts the addon manager.
 # Vars assumed:
 #   CLUSTER_NAME
@@ -2436,6 +2453,9 @@ EOF
   if [[ "${NETWORK_POLICY_PROVIDER:-}" == "calico" ]]; then
     setup-addon-manifests "addons" "calico-policy-controller"
 
+    setup-addon-custom-yaml "addons" "calico-policy-controller" "calico-node-daemonset.yaml" "${CUSTOM_CALICO_NODE_DAEMONSET_YAML:-}"
+    setup-addon-custom-yaml "addons" "calico-policy-controller" "typha-deployment.yaml" "${CUSTOM_TYPHA_DEPLOYMENT_YAML:-}"
+
     # Configure Calico CNI directory.
     local -r ds_file="${dst_dir}/calico-policy-controller/calico-node-daemonset.yaml"
     sed -i -e "s@__CALICO_CNI_DIR__@/home/kubernetes/bin@g" "${ds_file}"