Puppet没有将字符串隐式转换为整数

Question

我正在使用puppet管理具有多个后端的清漆服务器。我正在尝试创建一个循环，以便以后可以添加其他后端。到目前为止，我在erb文件中有以下内容：

<% @backends.each do |backend| -%>
backend <%= backend['backend_name'] %> {
    .host = "<%= @backend_addr %>";
    .port = "<%= backend['backend_port'] %>";
    .connect_timeout = 600s;
    .first_byte_timeout = 600s;
    .between_bytes_timeout = 600s;
}
<% end -%>

但是当这个运行时我得到错误：

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Failed to parse template varnish/drupal.vcl.erb:
  Filepath: /etc/puppet/modules/varnish/templates/drupal.vcl.erb
  Line: 17
  Detail: no implicit conversion of String into Integer
 at /etc/puppet/modules/varnish/manifests/init.pp:22 on node x.x.x.x

我做错了什么？