This is the most basic flat network, a single NATS broker with 1000s of Choria instances connected to it.
Use this to determine the top scale a certain spec NATS broker will handle unclustered, this is a good setup for a single Federation Member network, though you might want to test HA too.
You need gnatsd running on one of the NATS servers where all the nodes can connect to, a simple TLS free gnatsd can be started with:
# ulimit -n 200000
# gnatsd -T -m 8222 -p 4222
NOTE the ulimit above should be set to enough, NATS in it's current version will not log about out of file handles except in debug, so set to very high.
Lets say for example this is running on 192.168.1.1:4222
We'll run 100 instances per node, 10 agents and 5 sub collectives:
$ mco playbook run start-emulator.yaml --agents 10 --collectives 5 --instances 100 --servers 192.168.1.1:4222
After your tests you can stop it using:
$ mco playbook run stop-emulator.yaml
You'll need a special client cfg to connect to this network, save it in emulator-client.cfg:
plugin.choria.middleware_hosts = 192.168.1.1:4222
# for very large networks you'll need to do some tweaks here
discovery_timeout = 5
collectives = mcollective
connection_timeout = 3
connector = nats
identity = emulator_client
libdir = /opt/puppetlabs/mcollective/plugins
logger_type = console
loglevel = warn
main_collective = mcollective
securityprovider = choria
plugin.choria.security.serializer = json
plugin.choria.use_srv_records = false
Run the scenario using measure-collective.rb --config emulator-client.cfg with additional options for amount of tests etc