This demonstrates how lightweight xcluster is. 100 VMs are started
on a Dell XPS13 9370 with 16G ram. This example is mostly a show-off
since I can't put much load on the VMs on my laptop, but it can be
useful for some network testing and on more powerful computers.
The default hd-image is used and the VMs are started with a minimum of ram per VM. All VMs can (normally) not be started simultaneously without problems so we start 20 VMs at the time. Use "starts" rather than "start" to avoid 100 xterm's.
unset __mem1
export __mem=64
export __image=$XCLUSTER_WORKSPACE/xcluster/hd.img
xc mkcdrom xnet; xc starts --nrouters=0 --nvm=20
Do some initial experimenting, for instance login to a node and ping another;
vm 17
# On the vm;
ping 192.168.1.11
free
Now start the rest of the VMs by repeated "scaleout". Watch you CPU and let thing cool off between the scaleouts;
xc scaleout $(seq 21 40)
# wait...
xc scaleout $(seq 41 60)
# wait...
xc scaleout $(seq 61 80)
# wait...
xc scaleout $(seq 81 100)
# wait...
On my laptop the CPU load is ~30-40% with 100 VMs. Note that
xcluster is designed for max 200 nodes. The cap is imposted by the
network addressing and may be ovecome by ovls (but it's not trivial).