Cluster inside firewall

We now explain the case of using clusters from outside of firewalls. When there are firewall(s), it is necessary at least to access with ssh to the cluster server host. If you can not use anonymous ports without a port (#22) of ssh, you can use the function of multiplex communication with the agent. We show the hostfile for this example.

<?xml version="1.0" ?>
<OmniRpcConfig>
   <Host name="hpc-serv.hpcc.jp" arch="i386" os="linux">
   <Agent invoker="ssh" mxio="on" />
   <JobScheduler type="rr" maxjob="4" />
   </Host>
</OmniRpcConfig>

Set the mxio attribute "on" in the agent element and use the function of multiplex communication.

In environments which use Globus Toolkit, usually there are no firewalls, so you don't have to prepare. But, you have to set the mxio attribute in the same manner if the clusters consist of private IP addresses.

The relationship between the agent and rex is shown by the figure below.

Communications between the client and rex, which are executed on remote node hosts are relayed by the agent. And communications between the agent and clients are relayed by SSH's port forwarding through the firewall.