If graph not showing in centreon than you need to check several things as below.
By default, the graph files (.rrd) are stored in /var/lib/centreon/metrics, it is obviously necessary to have enough space in your filesystem.
Can the .rrd files be written in the /var/lib/centreon/metrics directory? Process that usually writes in this directory is either centstorage or cbd.
Does your plugin return the correct output? Refer to the Plugin API documentation for more information
Centreon Broker must be configured properly, refer to this documentation for more information.
The cbd rrd daemon must be running:
$ /etc/init.d/cbd status
* cbd_central-rrd is running
Make sure to have the Start script for broker daemon parameter filled in Administration > Options > Monitoring.
Source : Centreon Graph issues