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Access restricted to DataTAG members and U.S. partners
Rules and Guidelines for Using the DataTAG Testbed
The DataTAG testbed is an international research facility shared by many researchers all over the world. It consists of:
For a more detailed description of this testbed, here are three network maps:
Users who experience problems and new users who need to set up a new account should contact the support staff:
Public PCs vs. Private PCs
Public PCs are shared by many people, who use them either concurrently or sequentially. They are jointly managed by CERN and Caltech. The following PCs are public:
Private PCs are dedicated to a single research institute:
Private PCs are managed independently of the public PCs.
Public PCs and the 2.5 Gbit/s link are by default allotted to Europe-based users during the following time range:
Public PCs and the 2.5 Gbit/s link are by default allotted to U.S.-based users during the following time range:
As of January 13, 2003, all public PCs are rebooted at the end of each timezone, that is, twice per day. Upon reboot, time is synchronized via NTP on these PCs.
Default Pre-Allocation Scheme
Without making hard reservations, people can work on public PCs that are "allotted" to them as development machines during their timezones. They can safely assume that no one else will log into their machine and cause major disruption to it, e.g. reboot it. Other people can still log into their machine and put a light load onto it, but they know that the primary user for that PC may reboot it anytime.
During the European timezone, PCs are pre-allocated by default as follows :
During the U.S. timezone, PCs are pre-allocated by default as follows :
While doing is M.S. thesis at CERN, Simon Leo developed a reservation application that enables users to make hard reservations for resources. These resources include the ten public PCs of the testbed (five on each side of the Atlantic) and the 2.5 Gbit/s link.
The purpose of hard reservations is to prevent other users from causing disruption and generating background noise traffic while you make measurements and gather data for writing scientific reports. It is not to perform mere development work, unless this work may cause severe disruption to others (e.g., you need to change QoS parameters on the Cisco routers, which may hang the routers as we have already experienced).
We recommend that users reserve resources for 4 hours in a row, with a maximum of 8 hours. This policy is not currently enforced.
The five public PCs at CERN and the five public PCs in Chicago are now controlled by the DataTAG reservation application. The different timezones are properly dealt with: in all GUIs, users see times expressed in their own timezones.
The following features have been implemented:
The following features may be implemented in future releases:
Because the PCs of the DataTAG testbed are located outside firewalls, they are more exposed to attacks than others. The number of services available on these PCs is therefore kept to a strict minimum. In particular, telnet access is disabled. The only way to access these PCs is via ssh.
People who need to become root on a public PC first have to ssh under their user account, then do "ssh root@localhost".
Several users have root access to public PCs because they need to perform privileged commands, e.g. debug a new kernel.
Rule: The fact that you have root access does not allow you to reconfigure anything you want on a public PC. People who abuse of the root account will no longer be allowed to use the testbed. If you need to alter boot scripts, root account settings, etc., please contact support staff.
Default Linux Kernel
On all the public PCs at CERN and StarLight, the default Linux kernel is 2.4.24dtg6. This is the vanilla 2.4.24 kernel with the following modifications:
Rule: The default Linux kernel must not be changed by users.
How to Use Another Linux Kernel
/sbin/lilo -R kernel
Rule: People who do not run the default kernel must use this command to use another kernel. Changing lilo.conf and making your own kernel the default on that machine is considered antisocial.
Problem with Intel Device Driver
The Intel e1000 device driver is not included in the Linux kernel 2.4.19 by default (it is in version 2.4.20). If a user puts in a new kernel based on 2.4.19 and forgets to include this driver, access through the FastEthernet is no longer possible. Since the FastEthernet cards are the administrative interfaces on all public PCs, this breaks all of our administration tools.
Rule: People who install their own pre-2.4.20 kernel must include the Intel device driver.
If need be, Tom Kelly has made a patch available at:
This page is maintained by J.P. Martin-Flatin, Technical Manager, DataTAG Project.(last updated on 8 January 2004)
DataTAG is a project sponsored by the European Commission - EU Grant IST-2001-32459