Expanded SELinux UCP install documentation (#9299)

* Expanded SELinux install documentation

Added a bit more context installing UCP on a system with SELinux enabled
at the daemon.

* Added a list for cloud providers

ee/ucp/admin/install/index.md

@@ -78,10 +78,11 @@ To install UCP:
       --interactive
     ```
 
-    This runs the install command in interactive mode, so that you're
-    prompted for any necessary configuration values.
-    To find what other options are available in the install command, check the
-    [reference documentation](/reference/ucp/3.2/cli/install.md).
+    This runs the install command in interactive mode, so that you're prompted
+    for any necessary configuration values.  To find what other options are
+    available in the install command, including how to install UCP on a system
+    with SELinux enabled, check the [reference
+    documentation](/reference/ucp/3.2/cli/install.md).
 
 > Custom Container Networking Interface (CNI) plugins
 >

reference/ucp/3.2/cli/install.md

@@ -9,9 +9,12 @@ Install UCP on a node
 ## Usage
 
 ```bash
-docker container run --rm -it \
+docker container run \
+    --rm \
+    --interactive \
+    --tty \
     --name ucp \
-    -v /var/run/docker.sock:/var/run/docker.sock \
+    --volume /var/run/docker.sock:/var/run/docker.sock \
     docker/ucp \
     install [command options]
 ```
@@ -34,11 +37,48 @@ firewall:
   * 12376, 12379, 12380, 12381, 12382, 12383, 12384, 12385, 12386, 12387
   * 4789 (udp) and 7946 (tcp/udp) for overlay networking
 
-If you have SELinux policies enabled for your Docker install, you will need to
-use `docker container run --rm -it --security-opt label=disable ...` when running this
-command.
+### SELinux
 
-If you are installing on Azure, see [Install UCP on Azure](/ee/ucp/admin/install/install-on-azure/).
+If you are installing UCP on a manager node with SELinunx enabled at the daemon
+and operating system level, you will need to pass `--security-opt
+label=disable` in to your install command. This flag will disable SELinux
+policies on the installation container.  The UCP installation container mounts
+and configures the Docker Socket as part of the UCP installation container,
+therefore the UCP installation will fail with a permission denied error if you
+fail to pass in this flag.
+
+```
+FATA[0000] unable to get valid Docker client: unable to ping Docker daemon: Got
+permission denied while trying to connect to the Docker daemon socket at
+unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/_ping: dial
+unix /var/run/docker.sock: connect: permission denied - If SELinux is enabled
+on the Docker daemon, make sure you run UCP with "docker run --security-opt
+label=disable -v /var/run/docker.sock:/var/run/docker.sock ..."
+```
+
+An installation command for a system with SELinux enabled at the daemon level
+would be:
+
+```bash
+docker container run \
+    --rm \
+    --interactive \
+    --tty \
+    --name ucp \
+    --security-opt label=disable \
+    --volume /var/run/docker.sock:/var/run/docker.sock \
+    docker/ucp \
+    install [command options]
+```
+
+### Cloud Providers
+
+If you are installing on a public cloud platform there is cloud specific UCP
+installation documentation:
+
+- For [Microsoft Azure](./cloudproviders/install-on-azure/) this is
+  **mandatory**
+- For [AWS](./cloudproviders/install-on-aws/) this is optional.
 
 ## Options