Responsible Use of the Login Servers
CAEN does not allow remote login access to CAEN lab Linux computers from outside the U-M network. In order to provide some means for users to log into lab computers from home, CAEN set up the login servers. These are the only hosts that are accessible directly from off-campus. To connect to this pool of machines, one should use login.engin.umich.edu as the host name. The login servers are meant as a gateway to the rest of CAEN. When a CAEN user requires access to a CAEN lab machine from off-campus, they should first connect to login.engin.umich.edu, and subsequently connect to the lab machine.
Note: The login servers are for interactive use only, and should not be used for CPU-intensive and/or background work.
CAEN is notified when large and/or re-spawning background and/or CPU-intensive processes are being run on any of the CAEN login servers. Policy states that these servers are meant for interactive use only, for example running pine, ssh to a lab host, or using a text editor. Thousands of CAEN users rely on the login servers, and it is unacceptable for one user to monopolize a common resource to the detriment of others. Due to the nature of a violation of this policy, CAEN reserves the right to take action to stop the abuse from continuing. For example, CAEN reserves the right to stop/kill any large processes on the login servers, restrict any user's access to the login servers, or restrict access of a user's CAEN account from logging into any CAEN machine altogether.
CAEN asks all of its users to refrain from running large or re-spawning background and/or CPU-intensive jobs on the CAEN login servers. If you need to run these types of jobs, there are alternative resources available. Up to 10 lab hosts may be used simultaneously for such tasks. Permission is required beyond 10 hosts. A list of hosts may be obtained using the hostinfo command, or the HostInfo web page. Also, users can use the CAEN Computing Grid to submit as many jobs as you need to multiple lab hosts.
We encourage all CAEN account holders to use the Grid instead of ad hoc or manual job spawning techniques.
