Distributed test


Loads comes with no security whatsoever. If you run a broker, make sure that you secure access to the box because any code can be executed remotely through the loads-runner command.

The best way to avoid any issue is to protect the server access through firewall rules.

If you want to send a lot of load, you need to run a distributed test. A distributed test uses multiple agents to do the requests. The agents can be spread across several boxes called nodes.

A typical setup is to run a broker on a box, with a few agents, and have dedicated boxes to run many agents. This setup is called a Loads cluster.

The typical limiting factor will be the number of sockets each box will be able to open on each node that will call your service. This number can be tweaked by changing the ulimit value to a higher number - like 8096. You can read this page for more tips on tweaking your servers.

Setting up a Loads cluster

To run a broker and some agents, we can use Circus - a process supervisor.

To install Circus you can use Pip:

$ bin/pip install circus

If you have any trouble installing Circus, check out its documentation.

Once Circus is installed, you can run it against the provided loads.ini configuration file that’s located in the Loads source repository in the con/ directory:

$ bin/circusd --daemon conf/loads.ini

This command will run 1 broker and 5 agents

Here is the content of the loads.ini file:

check_delay = 5
httpd = 0
statsd = 1
debug = 0

cmd = bin/loads-broker
warmup_delay = 0
numprocesses = 1

cmd = bin/loads-agent
warmup_delay = 0
numprocesses = 5
copy_env = 1

Let’s control that the cluster is functional by pinging the broker for its status:

$ bin/loads-runner --ping-broker
Broker running on pid 11154
5 agents registered
- publisher: ipc:///tmp/loads-publisher.ipc
- frontend: ipc:///tmp/loads-front.ipc
- register: ipc:///tmp/loads-reg.ipc
- receiver: ipc:///tmp/loads-broker-receiver.ipc
- heartbeat: ipc:///tmp/hb.ipc
- backend: ipc:///tmp/loads-back.ipc
Nothing is running right now

Let’s use them now, with the agents option, with the example shown in Writing load tests:

$ bin/load-runner example.TestWebSite.test_something -u 10:20:30 -c 20 --agents 5
[======================================================================]  100%

Congrats, you have just sent 6000 hits from 5 different agents. Easy, no?

To stop your cluster:

$ bin/circusctl quit

Adding more agents


Detach mode

When you are running a long test in distributed mode, you might want to detach the console and come back later to check the status of the load test.

To do this, you can simply hit Ctrl+C. Loads will ask you if you want to detach the console and continue the test, or simply stop it:

$ bin/load-runner example.TestWebSite.test_something -u 10:20:30 -c 20 --agents 5
Duration: 2.04 seconds
Hits: 964
Started: 2013-07-22 07:12:30.139814
Approximate Average RPS: 473
Average request time: 0.00s
Opened web sockets: 0
Bytes received via web sockets : 0

Success: 964
Errors: 0
Failures: 0

Do you want to (s)top the test or (d)etach ? d

Then you can use –attach to reattach the console:

$ bin/loads-runner --attach
[                                       ]   4%
Duration: 43.68 seconds
Hits: 19233
Started: 2013-07-22 07:12:30.144859
Approximate Average RPS: 0
Average request time: 0.00s
Opened web sockets: 0
Bytes received via web sockets : 0

Success: 0
Errors: 0
Failures: 0

Do you want to (s)top the test or (d)etach ? s