Disable Regular User Login

This section provides guidelines to disable the ability for those with the USER level of privilege to log onto selected tasker machines. Most often, for better throughput, this is applied to use selected machines as part of a computing resource pool exclusively through Accelerator.

Note: Disabling the login to a vovtasker is not a normal or supported use of VOV functionality.

Disabling user login to the selected tasker machines is done in two phases:

  1. Disable user logins
  2. Set up vovtsd

Phase 1

  1. Disable all user logins except for the superuser or root on the selected machine.
  2. Create the file /etc/nologin. The content of the file will be the message the users receive when they try to login.
    An example of /etc/nologin on host h01 is shown below:
    % cat /etc/nologin
    Login disabled. Contact admin for help.
    When a regular (non-root) user tries to login, the message shown to the user will be as follows:
    % rlogin -l john h01
    john's Password:
    Login disabled. Contact admin for help.
    
    login:

Phase 2: Set Up vovtsd When login is disabled for the USER level and VOV ADMIN is typically not a root user, it is not possible to use rsh or ssh to either start or stop taskers from remote machines, such using the command vovtaskermgr. In this scenario, vovtsd can be used to manage the tasker machines remotely.

  1. Log onto the machine as root, switch to VOV ADMIN and then start vovtsd.
  2. From a remote machine, start or stop a tasker on this machine using a previously used method, such as using the command vovtaskermgr or ncmgr reset, the GUI or a browser.
    % su - vncadmin
    % vovtsd -normal
  3. Step 4 assumes that the shell for user "vncadmin" is set up to run the VOV software. Some accounts do not have this setup. In that case, the vovboot script could be used to start vovtsd.
    % su - root
    % /full/path/to/vov/installation/common/scripts/vovboot vovtsd -normal

To start vovtsd at boot time, consider deployment of the S99vovtsd script, a copy of which can be found in the directory $VOVDIR/etc/boot/S99vovtsd. Copy this script into /etc/rc3.d/S99vovtsd and customize it to fit the installation requirements.

  • Ensure that vovtsd is running.
  • Automatically restart vovtsd on reboot of the machine. This enables the machine to provide continuous computing power without having to log in as root and manually start vovtsd.
Note: If vovtsd is already running on a host and starting another host is tried, that second host will not start because the port is already occupied; starting vovtsd on a regular basis is a good way to ensure it is always running. Keeping the host running can be done with a cron job as shown in the example below:
% su - vncadmin% crontab -e
# Start vovtsd every thirty minutes
1,31 * * * *  /full/path/to/VOV/common/scripts/vovboot vovtsd -normal > /dev/null 2>&1