Add kubelet_custom_flags to kubelet.kubeadm.env.j2

roles/kubernetes/node/templates/kubelet.kubeadm.env.j2

@@ -54,7 +54,7 @@ KUBELET_HOSTNAME="--hostname-override={{ kube_override_hostname }}"
 {% set kubelet_args_dns %}{{ kubelet_args_cluster_dns }} --cluster-domain={{ dns_domain }} --resolv-conf={{ kube_resolv_conf }}{% endset %}
 
 
-KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kubelet_reserve }}"
+KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kubelet_reserve }} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}"
 {% if kube_network_plugin is defined and kube_network_plugin in ["calico", "canal", "flannel", "weave", "contiv"] %}
 KUBELET_NETWORK_PLUGIN="--network-plugin=cni --cni-conf-dir=/etc/cni/net.d --cni-bin-dir=/opt/cni/bin"
 {% elif kube_network_plugin is defined and kube_network_plugin == "cloud" %}