Thanks for replying.
the port should be fine. 
what i want to confirm is that in  -Dflume.monitoring.hosts=  
should the host be the address of  gmetad or the gmond?  
currently, i have 3 machines, like m1,m2,m3
i installed  gmetad on m2, and gmond on all of the 3 machines. 
from the ganglia ui, i can see  the system metrics of the 3 machines(nodes), however what i want is the flume metrics running on m1.

this is the port related config in gmetad.conf 

# The port gmetad will answer requests for XML
# default: 8651
# xml_port 8651
# The port gmetad will answer queries for XML. This facility allows
# simple subtree and summation views of the XML tree.
# default: 8652
# interactive_port 8652

Subject: 回复:agent monitoring with ganglia
Date: Thu, 15 Jan 2015 13:07:42 +0800

check you ganglia server firewall configure if allowed the port 8649 data input

------------------ 原始邮件 ------------------
发件人: "Ge Zhu";<>;
发送时间: 2015年1月15日(星期四) 上午10:05
收件人: ""<>;
主题: agent monitoring with ganglia

I set up a ganglia(3.6) server to  monitor the flume agent with the configured as below:
JAVA_OPTS="-Xms500m -Xmx500m -Dflume.monitoring.type=ganglia

however, after i start the flume agent, there is no graph for flume metrics show in the ganglia ui.
Do i need to install the gmond in the machine that running flume agent? or is there any configuration  i need to do?