Automatically running the same test plan multiple times with different variables - jmeter

Question

I've created a test plan to do some load testing against HTTP endpoints. I want to run the same test plan against multiple endpoints, and find myself having to do the following each time:
Change variable that determines which endpoint I'm hitting.
Run the test.
When complete, record results.
Clear all results.
Back to step 1.
I want to automate this. Is the following possible?
Define a list of endpoints as a variable.
For each endpoint in endpoints
Run test against endpoint
When complete, save results
Clear all results.
The things in particular that I don't know how to automate are:
Starting a test
Defining an list-style variable
Clearing all results
Any help would be greatly appreciated!

Answer 1

Please see answers below:
Starting a test
Apart from running JMeter from GUI there are several execution options such as:
Command line non-GUI mode - you can wrap JMeter execution line in operating system batch file
JMeter Ant Task - integration with Apache Ant build system, more powerful if you're comfortable with it
JMeter Maven Plugin - the same as Ant but for Apache Maven
Option to run JMeter with CI systems like Jenkins
Defining an list-style variable
JMeter offers "properties" which can be set via .properties files (see user.properties in /bin folder of your JMeter installation for example) or passed as name/value pairs to JMeter startup script. For instance instead of hard-coding your host in .jmx file you can use read a property function.
Set "Server Name or IP" field value to ${__P(myhost,)}
Add myhost=example.com line to user.properties file in /bin folder of your JMeter installation, restart JMeter and run the test. Request will go to example.com.
Alternatively you can pass myhost property to JMeter in command-line mode as follows
jmeter -Jmyhost=example.com
Multiple properties can be passed this way:
jmeter -Jproperty1=value1 -Jproperty2=value2 ....
And even files via -p or --propfile JMeter command line argument
See Apache JMeter Properties Customization Guide for more options and information.
Clearing all results
It depends on unattended execution option you'll choose, all of them provide at least one way to delete file and/or folder. Personally I wouldn't delete any results and would rather keep them for future reference. To distinguish different endpoints test runs and to avoid overwriting I would use timestamps like:
jmeter -Jhttp.endpoint=my.test.host -n -t your-script.jmx -l my-test-host-results-${date}.jtl
where
-J - sets endpoint to my.test.host
-n - tells JMeter to run in non-GUI mode
-t - specifies .jmx file to use
-l - specifies name and location of results file