how to send tag when using server attribute in fluentd

Question

I am very new to fluentd so this may be a very basic question. I want to send the data from my one fluentd to another one directly (using the <server> attribute) instead of writing to the file system, but not I am not able to find a way to send the tag with the <server> attribute.

What I've tried is:

<match testString>
  type forward
  buffer_chunk_limit 1m
  buffer_queue_limit 6000
  flush_interval 5s
  flush_at_shutdown true
  heartbeat_type tcp
  heartbeat_interval 3s
  num_threads 50
  <server>
    host **.**.**.****
    port ******
    tag testTagName
  </server>
</match>

But when I ran the config it gives me:

2016-03-11 13:33:41 +0000 [warn]: parameter 'tag' in <server>
  host **.**.**.***
  port *****
  tag testTagName
</server> is not used.

Answer 1

I dont think tag will work in <server> attribute. Instead you can forward logs to remote fluentd-aggregator at port 24224 and there you could use tag in <source> attribute of fluentd-aggregator's config file.

fluend-forwarder.conf

<match testString>
type forward
buffer_chunk_limit 1m
buffer_queue_limit 6000
flush_interval 5s
flush_at_shutdown true
heartbeat_type tcp
heartbeat_interval 3s
num_threads 50
<server>
   host **.**.**.****
   port 24224
</server>
</match>

fluentd-aggregator.conf

<source>
  @type forward
  port 24224
  tag testTagName
</source>

<match testTagName>
  ...
</match>