Configure the Xen hypervisors

Just check that your Xen hypervisor allows live migrations. More informations about using its configuration are available on this page .

Configure the Ganglia environment

1. Check that the Domain-0 and the virtual machines are monitored. Datas must be accessible from a gmeta daemon.
2. Create a script, that define the values of the additional metrics with xen tools. This script must be executed in the Domain-0 and must be able to execute gmetric and xenstore-* . Here is a sample script that consider the situation of the Domain-0 (more informations on this page ):

   #!/bin/sh
   OPTS="-c /etc/ganglia/gmond.conf"
   
   #We consider the memory consumption of the Domain-0
   dom0_memory=`xenstore-read /local/domain/0/memory/target`
   gmetric $OPTS -n container.mem_total \
                 -v $((`xm info|grep total_memory |cut -d ':' -f 2` * 1024 - $dom0_memory)) -u KB -t uint32 -s zero
   gmetric $OPTS -n container.cpu_num \
                 -v `xm info|grep nr_cpus| cut -d ':' -f 2` -t uint8
   gmetric $OPTS -n container.type -v xen-3.3 -t string -s zero
   gmetric $OPTS -n container.driver.migration -v xen -t string -s zero
   
   #List the VMs on the node (we omit the Domain-0)
   while [ true ]; do      
     vms="`xenstore-ls /local/domain|grep "name ="|grep -v Domain-0|cut -d '"' -f 2`"
     gmetric $OPTS -n container.vms \
                   -v "$vms"  -t string -s zero
     sleep 1
   done

Configure Entropy

First Get a distribution of Entropy and follow the installation instructions . Then look at the main configuration file "config/entropy.properties ".

1. Specify if necessary the address and eventually the port of the gmeta daemon
2. Adapt the solving time for both the vmpp and the vmrp (properties dynamicConsolidation.vmpp.solvingTime and dynamicConsolidation.vmrp.solvingTime )
3. If your virtual machines does not execute pure CPU intensive applications, desactivate the simplification of the configurations (property dynamicConsolidation.simplify.activate )..

   For detailled informations about the configuration of entropy, refer to this page .

Launch Entropy

Launch entropy by executing "./bin/controlLoop.sh start " in the base directory of the distribution. Entropy acts as a daemon, all its activity is logged into the ./logs directory. entropy.log contains informations related to the activity of the reconfiguration engine.

You can stop entropy by executing "./bin/controlLoop.sh stop " in the base directory of the distribution. This operation may takes times as Entropy must set cluster in a coherent state.