First draft of CNI plugin topic (#494)

* First draft of CNI plugin topic

* Fix for kubectl dependency issue

_data/toc.yaml

@@ -1759,6 +1759,8 @@ manuals:
         path: /ee/ucp/kubernetes/deploy-ingress-controller/
       - title: Create a service account for a Kubernetes app
         path: /ee/ucp/kubernetes/create-service-account/
+      - title: Install a CNI plugin
+        path: /ee/ucp/kubernetes/install-cni-plugin/
     - title: API reference
       path: /reference/ucp/3.0/api/
       nosync: true

ee/ucp/admin/install/index.md

@@ -87,6 +87,14 @@ To install UCP:
     To find what other options are available in the install command, check the
     [reference documentation](/reference/ucp/3.0/cli/install.md).
 
+> Custom CNI plugins
+>
+> If you want to use a third-party Container Networking Interface (CNI) plugin,
+> like Flannel or Weave, modify the previous command line to include the 
+> `--cni-installer-url` option. Learn how to
+> [install a CNI plugin](../../kubernetes/install-cni-plugin.md).
+{: important}
+
 ## Step 5: License your installation
 
 Now that UCP is installed, you need to license it.

ee/ucp/kubernetes/install-cni-plugin.md

@@ -0,0 +1,70 @@
+---
+title: Install a CNI plugin
+description: Learn how to install a Container Networking Interface plugin on Docker Universal Control Plane.
+keywords: ucp, cli, administration, kubectl, Kubernetes, cni, Container Networking Interface, flannel, weave
+ui_tabs:
+- version: ucp-3.0
+  orhigher: false
+next_steps:
+- path: ../admin/install/
+  title: Install UCP for production
+- path: ../kubernetes/
+  title: Deploy a workload to a Kubernetes cluster
+---
+
+{% if include.version=="ucp-3.0" %}
+
+With Docker Universal Control Plane, you can install a third-party Container
+Networking Interface (CNI) plugin when you install UCP, by using the
+`--cni-installer-url` option. By default, Docker EE installs the built-in
+[Calico](https://github.com/projectcalico/cni-plugin) plugin, but you can
+override the default and install a plugin of your choice,
+like [Flannel](https://github.com/coreos/flannel) or
+[Weave](https://www.weave.works/).
+
+# Install UCP with a custom CNI plugin
+
+Modify the [UCP install command-line](../admin/install/index.md#step-4-install-ucp)
+to add the `--cni-installer-url` [option](/reference/ucp/3.0/cli/install.md),
+providing a URL for the location of the CNI plugin's YAML file:
+
+```bash
+docker container run --rm -it --name ucp \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  {{ page.ucp_org }}/{{ page.ucp_repo }}:{{ page.ucp_version }} install \
+  --host-address <node-ip-address> \
+  --cni-installer-url <cni-yaml-url> \
+  --interactive
+```
+
+You must provide a correct YAML installation file for the CNI plugin, but most
+of the default files work on Docker EE with no modification.
+
+## YAML files for CNI plugins
+
+Use the following commands to get the YAML files for popular CNI plugins. 
+
+- [Flannel](https://github.com/coreos/flannel)
+  ```bash
+  # Get the URL for the Flannel CNI plugin.
+  CNI_URL="https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml"
+  ```
+- [Weave](https://www.weave.works/)
+  ```bash
+  # Get the URL for the Weave CNI plugin. 
+  CNI_URL="https://cloud.weave.works/k8s/net?k8s-version=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"
+  ```
+  If you have kubectl available, for example by using
+  [Docker for Mac](/docker-for-mac/kubernetes.md), you can use the following
+  command to get the URL for the [Weave](https://www.weave.works/) CNI plugin:
+  ```bash
+  # Get the URL for the Weave CNI plugin. 
+  CNI_URL="https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
+  ```
+- [Romana](http://docs.romana.io/)
+  ```bash
+  # Get the URL for the Romana CNI plugin.
+  CNI_URL="https://raw.githubusercontent.com/romana/romana/master/docs/kubernetes/romana-kubeadm.yml"
+  ```
+
+{% endif %}

ee/ucp/user-access/kubectl.md

@@ -12,6 +12,8 @@ next_steps:
   title: Deploy to Kubernetes on Docker for Mac
 ---
 
+{% if include.version=="ucp-3.0" %}
+
 Docker EE installs Kubernetes automatically when you install UCP, and the
 web UI enables deploying Kubernetes workloads and monitoring pods. You can
 also interact with the Kubernetes deployment by using the Kubernetes
@@ -101,3 +103,5 @@ NAME             TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
 svc/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   5d
 ```
 
+{% endif %}
+