fluent/fluentd

<source>
  @type sample
  tag test
</source>
<source>
  @type sample
  tag test2
</source>
<source>
  @type sample
  tag test3
</source>

<match test>
  @type forward
  flush_interval 0
  <security>
    self_hostname output.testing.local
    shared_key    secure_communication_is_awesome
  </security>
  <server>
    host 127.0.0.1
    port 24224
    username user1
    password yes_this_is_user1
  </server>
</match>

<match test2>
  @type forward
  flush_interval 0
  <security>
    self_hostname output-alt1.testing.local
    shared_key    secure_communication_is_awesome
  </security>
  <server>
    host 127.0.0.1
    port 24224
    username user1
    password yes_this_is_user1
  </server>
  <server>
    host 127.0.0.1
    port 24224
    username user2
    password yes_this_is_really_user2
  </server>
</match>

<match test3>
  @type forward
  flush_interval 0
  <security>
    self_hostname output-fail.testing.local
    shared_key    secure_communication_is_awesome
  </security>
  <server>
    host 127.0.0.1
    port 24224
    username user3
    password no_there_are_not_such_user
    # input plugin warns authentication erro:
    # [warn]: Authentication failed address="127.0.0.1" hostname="output-fail.testing.local" username="user3"
  </server>
</match>