Merge pull request #23283 from sftim/20200820_improve_diagrams_for_in…

…gress

Switch Ingress concept to use MermaidJS diagrams

assets/scss/_custom.scss

@@ -61,6 +61,15 @@ body.td-404 main .error-details {
   margin-bottom: 0;
 }
 
+/* Global - Mermaid.js diagrams */
+
+.mermaid {
+  overflow-x: auto;
+  max-width: 80%;
+  border: 1px solid rgb(222, 226, 230);
+  border-radius: 5px;
+}
+
 /* HEADER */
 
 .td-navbar {
@@ -542,3 +551,4 @@ body.td-documentation {
     }
   }
 }
+

content/en/docs/concepts/services-networking/ingress.md

@@ -29,13 +29,24 @@ For clarity, this guide defines the following terms:
 {{< link text="services" url="/docs/concepts/services-networking/service/" >}} within the cluster.
 Traffic routing is controlled by rules defined on the Ingress resource.
 
-```none
-    internet
-        |
-   [ Ingress ]
-   --|-----|--
-   [ Services ]
-```
+Here is a simple example where an Ingress sends all its traffic to one Service:
+{{< mermaid >}}
+graph LR;
+  client([client])-. Ingress-managed <br> load balancer .->ingress[Ingress];
+  ingress-->|routing rule|service[Service];
+  subgraph cluster
+  ingress;
+  service-->pod1[Pod];
+  service-->pod2[Pod];
+  end
+  classDef plain fill:#ddd,stroke:#fff,stroke-width:4px,color:#000;
+  classDef k8s fill:#326ce5,stroke:#fff,stroke-width:4px,color:#fff;
+  classDef cluster fill:#fff,stroke:#bbb,stroke-width:2px,color:#326ce5;
+  class ingress,service,pod1,pod2 k8s;
+  class client plain;
+  class cluster cluster;
+{{</ mermaid >}}
+
 
 An Ingress may be configured to give Services externally-reachable URLs, load balance traffic, terminate SSL / TLS, and offer name-based virtual hosting. An [Ingress controller](/docs/concepts/services-networking/ingress-controllers) is responsible for fulfilling the Ingress, usually with a load balancer, though it may also configure your edge router or additional frontends to help handle the traffic.
 
@@ -274,10 +285,25 @@ A fanout configuration routes traffic from a single IP address to more than one
 based on the HTTP URI being requested. An Ingress allows you to keep the number of load balancers
 down to a minimum. For example, a setup like:
 
-```
-foo.bar.com -> 178.91.123.132 -> / foo    service1:4200
-                                 / bar    service2:8080
-```
+{{< mermaid >}}
+graph LR;
+  client([client])-. Ingress-managed <br> load balancer .->ingress[Ingress, 178.91.123.132];
+  ingress-->|/foo|service1[Service service1:4200];
+  ingress-->|/bar|service2[Service service2:8080];
+  subgraph cluster
+  ingress;
+  service1-->pod1[Pod];
+  service1-->pod2[Pod];
+  service2-->pod3[Pod];
+  service2-->pod4[Pod];
+  end
+  classDef plain fill:#ddd,stroke:#fff,stroke-width:4px,color:#000;
+  classDef k8s fill:#326ce5,stroke:#fff,stroke-width:4px,color:#fff;
+  classDef cluster fill:#fff,stroke:#bbb,stroke-width:2px,color:#326ce5;
+  class ingress,service1,service2,pod1,pod2,pod3,pod4 k8s;
+  class client plain;
+  class cluster cluster;
+{{</ mermaid >}}
 
 would require an Ingress such as:
 
@@ -321,11 +347,26 @@ you are using, you may need to create a default-http-backend
 
 Name-based virtual hosts support routing HTTP traffic to multiple host names at the same IP address.
 
-```none
-foo.bar.com --|                 |-> foo.bar.com service1:80
-              | 178.91.123.132  |
-bar.foo.com --|                 |-> bar.foo.com service2:80
-```
+{{< mermaid >}}
+graph LR;
+  client([client])-. Ingress-managed <br> load balancer .->ingress[Ingress, 178.91.123.132];
+  ingress-->|Host: foo.bar.com|service1[Service service1:80];
+  ingress-->|Host: bar.foo.com|service2[Service service2:80];
+  subgraph cluster
+  ingress;
+  service1-->pod1[Pod];
+  service1-->pod2[Pod];
+  service2-->pod3[Pod];
+  service2-->pod4[Pod];
+  end
+  classDef plain fill:#ddd,stroke:#fff,stroke-width:4px,color:#000;
+  classDef k8s fill:#326ce5,stroke:#fff,stroke-width:4px,color:#fff;
+  classDef cluster fill:#fff,stroke:#bbb,stroke-width:2px,color:#326ce5;
+  class ingress,service1,service2,pod1,pod2,pod3,pod4 k8s;
+  class client plain;
+  class cluster cluster;
+{{</ mermaid >}}
+
 
 The following Ingress tells the backing load balancer to route requests based on
 the [Host header](https://tools.ietf.org/html/rfc7230#section-5.4).
@@ -508,4 +549,3 @@ You can expose a Service in multiple ways that don't directly involve the Ingres
 * Learn about the [Ingress API](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#ingress-v1beta1-networking-k8s-io)
 * Learn about [Ingress controllers](/docs/concepts/services-networking/ingress-controllers/)
 * [Set up Ingress on Minikube with the NGINX Controller](/docs/tasks/access-application-cluster/ingress-minikube/)
-