I'm running multiple tests across a Selenium grid containing a multiple nodes, using a dynamically created Firefox profile, like this:

```
$firefoxProfile = new FirefoxProfile();
$capabilities = DesiredCapabilities::firefox ();
$capabilities->setCapability(FirefoxDriver::PROFILE, $firefoxProfile);

$this->webdriver = RemoteWebDriver::create("http://my.tests.com", $capabilities, 5000);

```

But every time the hub picks up a node with a previous running Firefox instance it uses the same profile and drops the previously running session. It happens because the application uses the same cookies for authentication purposes.

Is there some way to force selenium grid to create a new profile on the fly and get a totally new firefox instance?

Some further information
------------------------

For getting the hub started I currently use the following command line

```
    java -jar /opt/selenium/selenium-server.jar -trustAllSSLCertificates -timeout  300 \
                                        -role hub -newSessionWaitTimeout 60 -maxSession 2 \
                                        -port 9444 -nodeTimeout 300 \
                                        -browserTimeout 300 &

```

And to get nodes started I use

```
    xvfb-run -n 99 --server-args="-screen 0 800x600x16 -ac"  \
      -a java -jar /opt/selenium/selenium-server.jar -role node \
                 -browser browserName=firefox,maxInstances=2 \
                 -hub http://my.tests.com:9444/grid/register 

```

The weird thing is that when I set up a standalone Selenium server it creates multiple firefox instances as I would like to be...