Fix/improve documentation for ingress controller

Fixes #341

README.md

@@ -197,15 +197,15 @@ RKE will ask some questions around the cluster file like number of the hosts, ip
 
 ## Ingress Controller
 
-RKE will deploy Nginx controller by default, user can disable this by specifying `none` to `ingress` option in the cluster configuration, user also can specify list of options fo nginx config map listed in this [docs](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/configmap.md), for example:
+RKE will deploy Nginx controller by default, user can disable this by specifying `none` to ingress `provider` option in the cluster configuration, user also can specify list of options for nginx config map listed in this [doc](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/configmap.md), for example:
 ```
 ingress:
-  type: nginx
+  provider: nginx
   options:
     map-hash-bucket-size: "128"
     ssl-protocols: SSLv2
 ```
-RKE will deploy ingress controller on all schedulable nodes (controlplane and workers), to specify only certain nodes for ingress controller to be deployed user has to specify `node_selector` for the ingress and the right label on the node, for example:
+By default, RKE will deploy ingress controller on all schedulable nodes (controlplane and workers), to specify only certain nodes for ingress controller to be deployed, user has to specify `node_selector` for the ingress and the right label on the node, for example:
 ```
 nodes:
   - address: 1.1.1.1
@@ -215,7 +215,7 @@ nodes:
       app: ingress
 
 ingress:
-  type: nginx
+  provider: nginx
   node_selector:
     app: ingress
 ```

cluster.yml

@@ -32,8 +32,23 @@ network:
   plugin: flannel
   options:
 
+# Default ingress provider is nginx, To disable ingress, use
+# provider: none
+
+ingress:
+  provider: nginx
+  node_selector:
+    app: ingress
+  options:
+    map-hash-bucket-size: "128"
+    ssl-protocols: SSLv2
+
 ssh_key_path: ~/.ssh/test
+
+# ignore_docker_version toggle will enforce docker version support.
+# If ignore is enabled (true), rke will print out a non-fatal warning instead of error
 ignore_docker_version: false
+
 # Kubernetes authorization mode; currently only `rbac` is supported and enabled by default.
 # Use `mode: none` to disable authorization
 authorization:
@@ -56,6 +71,8 @@ nodes:
   - address: 2.2.2.2
     user: ubuntu
     role: [worker]
+    labels:
+      app: ingress
     ssh_key: |-
       -----BEGIN RSA PRIVATE KEY-----
 
@@ -65,6 +82,8 @@ nodes:
     role: [worker]
     hostname_override: node3
     internal_address: 192.168.1.6
+    labels:
+      app: ingress
 
 services:
   etcd: