Remote unix Learning Environment (RULE)
Application Overview
The JHT Administrator application is designed to
significantly reduce the time and effort spent using and maintaining the RULE
system.
Presently the application can be run from the primary host and displayed remotely
through an X client/server on a client machine. While most Unix variants support X,
Windows can also run remote X applications with the help of Cygwin (a free
download from http://www.cygwin.com.)
The JHT Administrator application has been designed with
flexibility and portability in mind, so future versions are likely to run natively on
the client machine and connect to a JHT server on the primary host machine.
JHT Administrator displays all configured jails on the primary
host in a tree structure, similar to that of Windows Explorer.
The is no restriction on the folder and resource configuration, however a
subject/class structure is recommended as it simplifies the assignment of shared
resources between jailed hosts.
Many functions available in the context menus affect nodes on and below the current
level, this significantly simplifies sharing resources between groups of jail hosts,
but does require an appropriate folder structure to work effectivly.
|
|
The Navigation Tree
 |
Hosts shown as grayed out are not running and do not have their file systems mounted. |
 |
Hosts not grayed out, but without any overlay, are not running but have their file systems mounted. |
 |
Hosts with a `Play' overlay are running normally. |
 |
Hosts with a red exclamation mark have some processes running, but sshd is not one of them. This means that it is not possible to log into the host via SSH, so it is considered a zombie. |
 |
Gold Cd's represent CD images. These CD images can be share among all hosts at the same level or below their location in the tree. |
 |
Gold Cd's with a green overlay are mounted but not shared |
 |
Gold Cd's with a green overlay and a hand are shared |
The Properties Window
Double-clicking on an item in the navigation tree causes information about that node to be displayed textually in the Properties window.
The Statistics Window displays statistical information about the active node in the tree.
Statistics in future versions will include:
- Total logins
- Average CPU utilization
- Network utilization
Creating a New Class of Virtual Hosts
Creating a new class of virtual hosts couldn't be easier, just create them
where you want them ... create directory for subject and lab date and time
then right click on the lab directory and select Create New Class
. This will bring up a dialog that allows you to enter the IP
address range for which you would like the virtual hosts to be created.
Virtual host creation is performed as a background task allowing you to
continue using the JHT Administrator for other jobs.
Virtual hosts enter a number of stages during installation, building,
copying and customising. When customisation is complete the root and user
passwords will have been set to a randomly generated pronouncable string of
letters and numbers.
Making Life Easier for Students, Lab Demonstrators and System Administrators
A task for Unix lab demonstrators is dealing with forgotton passwords.
Traditionally (on a shared Unix machine) fixing this problem would have been
up to the system administrator, this may or may not mean that a forgotten or
unintentionally changed password may be a problem that cannot be fixed during
the lab, wasting the student's allocated time in the lab.
With RULE a lab demonstrator can be given responsibility of the virtual hosts
in their lab and implict in that, the ability to (among other things) reset
forgotton passwords for their students. This not only allows the student to
make the most of their scheduled lab time, but is one less task a busy
system administrator has to perform.
JHT Administrator (if configured to do so) allows lab
demonstrators the ability to jump into a students virtual host even when
remote login over SSH is not functioning.
This can be useful in a number
of scenarios ...
- A student accidently kills sshd and locks
themseleves out of their virtual host.
The lab demonstrator
can restart the SSH daemon from within the virtual host so the
student can continue their work
- The lab demonstrator can easily reset root and
user passwords and other vital system settings from
a single location
An xterm open on a virtual host where sshd is not running (note icon)
Root and user passwords can also be reset directly from JHT Administrator's
virtual host context menu.
Changing the root password directly from the GUI
