Improve none usage documentation

pkg/minikube/reason/known_issues.go

@@ -92,6 +92,17 @@ var resourceIssues = []match{
 		},
 		Regexp: re(`An existing connection was forcibly closed by the remote host`),
 	},
+	{
+		// Fallback to deliver a good error message even if internal checks are not run
+		Kind: Kind{
+			ID:       "RSRC_INSUFFICIENT_CORES",
+			ExitCode: ExInsufficientCores,
+			Advice:   "Kubernetes requires at least 2 CPU's to start",
+			Issues:   []int{7905},
+			URL:      "https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/",
+		},
+		Regexp: re(`ERROR.*the number of available CPUs 1 is less than the required 2`),
+	},
 }
 
 // hostIssues are related to the host operating system or BIOS

site/content/en/docs/drivers/includes/none_usage.inc

@@ -2,16 +2,18 @@
 
 A Linux VM with the following:
 
-* Docker
-* systemd (OpenRC based systems are also supported in v1.10+)
+* systemd or OpenRC
+* a container runtime, such as Docker or CRIO
 
-This VM must also meet the [kubeadm requirements.](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/)
+This VM must also meet the [kubeadm requirements](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/), such as:
 
-Kubernetes v1.18+ needs conntract to be installed on debian based machines.
-
-```shell
-    sudo apt-get install conntrack -y
-```
+* 2 CPU's
+* 2GB RAM
+* iptables (in legacy mode)
+* conntrack
+* crictl
+* SELinux permissive
+* cgroups v1 (v2 is not yet supported by Kubernetes)
 
 ## Usage