add doc: bootstrap prereq for linux cgroup1 (#2220)

Signed-off-by: kcoriordan <[email protected]>

docs/site/content/docs/assets/prereq-linux.md

@@ -7,3 +7,25 @@
 |[Kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/) |
 |Latest version of Chrome, Firefox, Safari, Internet Explorer, or  Edge|
 |System time is synchronized with a Network Time Protocol (NTP) server.|
+|Ensure your Linux bootstrap machine is using cgroup v1, for more information, see **Check and set the cgroup** below.|
+
+#### Check and set the cgroup 
+
+1. Check the cgroup by running the following command:
+
+    ```sh
+    docker info | grep -i cgroup 
+    ```
+
+    You should see the following output:
+
+    ```sh
+    Cgroup Driver: cgroupfs
+    Cgroup Version: 1
+    ```
+
+2. If your Linux distribution is configured to use cgroups v2, you will need to set the `system.unified_cgroup_hierarchy=0` kernel parameter to restore cgroups v1. See the instructions for setting kernel parameters for your Linux distribution, including:
+
+    [Fedora 32+](https://fedoramagazine.org/docker-and-fedora-32/)  
+    [Arch Linux](https://wiki.archlinux.org/title/Kernel_parameters)  
+    [OpenSUSE](https://doc.opensuse.org/documentation/leap/reference/html/book-reference/cha-grub2.html)