Is it possible to know which node the selenium grid hub assigned to your test? My tests need to talk to other services on the node machine in order to perform configuration
Generally you shouldn't rely on knowing what machine your test is running on. Grid 2 provides a series of callback listeners that you could implement to provide machine configuration. But, if you really want to see what node a test is running on, you could use one of the API calls. Both endpoints can be found on the hub:
http://localhost:4444/grid/api/proxy
http://localhost:4444/grid/api/testsession
Neither are documented yet. But if you view the source, it's straightforward to see how they work. You want to look at the ProxyStatusServlet and TestSessionStatusServlet.
String hub = "grid_server_host"; //IP or hostname of GRID
int port = 4444; // port no.
HttpHost host = new HttpHost(hub,port);
DefaultHttpClient client = new DefaultHttpClient();
String url = host + "/grid/api/testsession?session=";
URL session = new URL(url + ((RemoteWebDriver) webdriver).getSessionId());
BasicHttpEntityEnclosingRequest req;
req = new BasicHttpEntityEnclosingRequest("POST", session.toExternalForm());
org.apache.http.HttpResponse response = client.execute(host,req);
JSONObject object = new JSONObject(EntityUtils.toString(response.getEntity()));
String proxyID = (String) object.get("proxyId");
String node = (proxyID.split("//")[1].split(":")[0]);