Group Manager Overview

GruMP protocol and the Group Manager

Network Interfaces

Configurable through the GroupManager configuration file grpMgr.properties (under aci/conf). The GroupManager requires to specify all the network interfaces that the component will use for the service discovery process. In order to complete this step, it is necessary to edit the property aci.groupmanager.netIFs. Each space-separated network interface can be specified with its current IP address. The syntax is the following:

# Syntax: IP_ADDR/ADVERTISEMENT_MODE

For each interface that is listed, it is required to add a / character, followed by the advertisement mode, to be chosen among the following ones:

UDP_BROADCAST UDP_MULTICAST UDP_MULTICAST_NORELAY XLAYER_BROADCAST XLAYER_MULTICAST

Example:

aci.groupmanager.netIFs=10.2.8.15/UDP_MULTICAST_NORELAY 192.168.250.2/UDP_MULTICAST

Configures two interfaces, one (10.2.8.15) in UDP_MULTICAST_NORELAY advertisement mode and the other one (192.168.250.2) in UDP_MULTICAST advertisement mode.

Debugging

Sometimes, when running GroupManager from the JNI Wrapper it is useful to analyse core dumps. To do this, enable core dumping in the JVM before running the GroupManager JNI with:

ulimit -c unlimited

Then, whenever a dump is produced (in this example, the file core) feed it to gdb along with the libgrpmgrjavawrapper.so (present in aci/bin) to see the stacktrace and other useful debug informations:

sudo gdb -c core libgrpmgrjavawrapper.so