This document shows how you can use JMeter to perform more automated (non-interactive) testing.

Requirements

This article assumes that you:

• know the basics of JMeter
• have an existing test plan
• have a bit of knowledge on using variables in test plans
• have touched on remote testing (from GUI is fine)
  

Set up

• In your existing test plan, make sure that any variations in testing make use of variables. For example, if running a HTTP sampler, use HTTP Request Defaults to specify a host as "${+P(targetHost)}". Other useful places for variables might include number of threads, ramp-up period or scheduler duration in a thread group, using a format of ${+P(threadgroup.threads,500)} (The +P function is shorthand for +parameter. See the userguide for more info on using this parameter).
• Save your test plan and properties file to a directory.
• Create a properties file containing all your variables. E.g. mytest.properties could contain threadgroup.threads=100, targetHost=my-target-host.com
• The test plan does not need Listeners, as this will be configured via parameters. This will improve performance on the testing.
• Run the test mode in stand-alone mode (i.e. no remote servers): jmeter -n -t load_test.jmx -l load_test_report.jtl -q mytest.properties -j mytest.log
• 1 small piece of functionality missing is the ability to set global variables from a property file. the "-q" parameter defines an additional property file, which is the equivalent of setting properties for the contents of the file using the -J parameter. This parameters are not global however, as would be set by the -G parameter. the following bash script (if your using Linux) would help with converting a properties file to global properties:

for var in `grep -vE "^(#|$)" mytest.properties`; do
  GLOBAL_VARS="-G${var} ${GLOBAL_VARS}"
done

This is a relatively simple bash expansion, and will break if there are any spaces in variable names or values (e.g. test.description="My Test" - the space would break the bash for loop.)

• On all client machines, start up JMeter server, ensuring that firewall is not blocking connections (clients must all be on the same subnet).
• On JMeter controller (the host initializing the test), run the test with the -R parameter (can be run using -r and specfiying hosts in jmeter properties file):
  jmeter -n -t load_test.jmx -l load_test_report.jtl -q mytest.properties -j mytest.log -R remotehost1,remotehost2 ${GLOBAL_VARS}
  

Note that load injection to targets will be a increased as a ratio of number of threads per thread group multiplied by number of client machines.

A script similar to the following could be used to start up jmeter:

#!/bin/sh

loadtest="myloadtest"
GLOBAL_VARS=""
REPORT_DIR=/tmp
JMETER_PROPERTIES=jmeter.properties
JMETER_CUSTOM_PROPERTIES=mytest.properties
# If set as an environment var, then use it, otherwise leave it unset.
HOST_LIST=${HOST_LIST:+"-R ${HOST_LIST}"}

for var in `grep -vE "^#|^$" ${JMETER_CUSTOM_PROPERTIES}`; do
	GLOBAL_VARS="-G${var} ${GLOBAL_VARS}"
done

if [ -f ${loadtest}.jmx ]; then
	echo "Running ${loadtest} with:"
	echo -e "		-----------------------
	$JMETER -n
		-t ${loadtest}.jmx
		-l ${REPORT_DIR}/${loadtest}.jtl
		-p ${JMETER_PROPERTIES}
		${GLOBAL_VARS}
		${HOST_LIST}
		-j ${REPORT_DIR}/_${loadtest}.log
	-----------------------"
	$JMETER -n \
		-t ${loadtest}.jmx \
		-l ${REPORT_DIR}/${loadtest}.jtl \
		-p ${JMETER_PROPERTIES} \
		${GLOBAL_VARS} \
		${HOST_LIST} \
		-j ${REPORT_DIR}/_${loadtest}.log
else
	echo "Could not find test plan for ${loadtest}"
fi