Update sample.

inventory/sample/group_vars/all.yml

@@ -155,3 +155,7 @@ bin_dir: /usr/local/bin
 
 # Does coreos need auto upgrade, default is true
 #coreos_auto_upgrade: true
+
+# Set true to download and cache container
+#download_container: true
+

inventory/sample/group_vars/k8s-cluster.yml

@@ -135,6 +135,14 @@ skydns_server_secondary: "{{ kube_service_addresses|ipaddr('net')|ipaddr(4)|ipad
 dnsmasq_dns_server: "{{ kube_service_addresses|ipaddr('net')|ipaddr(2)|ipaddr('address') }}"
 dns_domain: "{{ cluster_name }}"
 
+# Use docker as container runtime
+# If you set manage_crio true, set manage_docker false.
+manage_docker: true
+
+# Use cri-o as container runtime
+# If you set manage_docker true, set manage_crio false.
+manage_crio: false
+
 # Path used to store Docker data
 docker_daemon_graph: "/var/lib/docker"