Encryption at rest is only support on kubernetes 1.7 and later

Author: simonswine

puppet/modules/kubernetes/templates/kube-apiserver.service.erb

@@ -82,7 +82,7 @@ ExecStart=<%= scope['kubernetes::_dest_dir'] %>/apiserver \
 <%- if scope['kubernetes::_service_account_key_file'] -%>
   --service-account-key-file=<%= scope['kubernetes::_service_account_key_file'] %> \
 <% end -%>
-<%- if @encryption_config_file -%>
+<%- if @post_1_7 and @encryption_config_file -%>
   --experimental-encryption-provider-config=<%= @encryption_config_file %> \
 <% end -%>
 <%- if scope.function_versioncmp([scope['kubernetes::version'], '1.9.0']) >= 0 -%>