Note: I removed the duplicate of this post from the forums.
2.7.x and 3.0.0 BETA AGENTS ON SAME *NIX HOST
You can install a 3.0.0 beta agent on a host already running a 2.7.x agent. We are doing this in our demo environment currently. When you untar the downloaded agent, you get a directory named "hyperic-hq-agent-3.0.0". I like to rename the beta directories with the build number, so something like "hyperic-hq-agent-3.0.0-242" works for me. Then I..
* cd into the new agent directory
* edit the agent.properties file, adding the line:
agent.listenPort=2145
Note: this port just needs to be an unused port, and most importantly, cannot be the same port in use by your other agent.
* go through the typical agent startup process, making sure to specify the new 3.0 server IP and port, and accept the new port default you've set for the agent.
2.7.x and 3.0.0 BETA SERVER ON THE SAME *NIX HOST
Running multiple copies of the HQ Server on the same host is not supported or recommended, even for test.