GAHnix

News | Features | Requirements | Links | Tested DC Clients | Download | Installation | Using GAHnix | Copyright

Development News

Features

• RAM disk operation
• Boot floppy (initital system)
• No hard drive needed
• Network loading of package modules
• Kernel 2.2.19
• glibc 2.1
• SSH
• NFS
• bash
• TuxTime client

Requirements

GAHnix Central Server

• Linux Installation
• Local Area Network installed and running
• Apache HTTP server installed and running
• Network File System (NFS) installed and running
• OpenSSH installed and configured

GAHnix Node

• Intel 486 or higher
• 32MB RAM (64MB or more preffered, see the client table)
• 3.5" 1.44MB Floppy Drive
• 10/100Mbps Ethernet Network Card:-
• 3Com Etherlink 509 series (ISA)
• 3Com Etherlink 590/905 series (PCI)
• Realtek 8139 (PCI)
• NE2000/Realtek 8129 (PCI)
• NE2000 (ISA)A (Most old ISA NIC's)
• AMD PCNet 32
• Intel EtherExpress Pro 10/100
• SMC EtherPower II
• DEC Tulip

Links to Related Pages

• GAHnix Support Forums
• A users perspective on GAHnix
• Trinix Linux Security Toolkit
• NFS HOWTO
• DNS HOWTO
• IP Masquerade HOWTO
• Apache HOWTO

Tested Distributed Computing Clients

Download

Below is a list of all files of the project. Download both files to your local Linux machine as per the installation instructions.

File	Arch.	Date	Size	Description
gahnix.img	i486	Aug 25 13:32	1474560	GAHnix Boot Image
gahnix_modules.tgz	i486	Aug 25 12:54	3350308	GAHnix Module Tarball

Installation

Overview

The installation process consists of several stages, follow each stage in logical order. Installation involves setting up the following equiempent and software, note that the Central Server and Workstation may be the same machine:

• A Central Linux Server
• A Linux Workstation
• Any number of GAHnix Nodes

Preparing the Central Server

This part of the installation assumes the default Apache installation, with your public HTML at /var/www/html/
Refer to the Apache HOWTO for a more detailed guide to installing and configuring Apache.
Refer to the NFS HOWTO for a more detailed guide on installing and configring NFS.
The following steps are performed on the central server as root:

1. Setting up the GAHnix modules under Apache, to be used by all GAHnix nodes
1. Make a new directory called: /var/www/html/gahnix
2. Download the GAHnix module tarball into the directory /var/www/html/gahnix/
3. Unpack the tarball: tar -zxvf gahnix_modules.tgz
4. Test the Apache server by pointing your browser to: http://localhost/gahnix
   You should see a filelist, listing the 21 packages contained in /var/www/html/gahnix
2. Setting up NFS shares for each GAHnix node
1. Create a new directory for each GAHnix node. ie. /exports/cruncher1
2. Create a temporary directory for the GAHnix node. ie. /exports/cruncher1/tmp
3. Add the new share to your NFS configuration, by editing /etc/exports, for example:
   

       /exports/cruncher1 	(rw,no_root_squash,insecure)

4. Repeat steps i to iii for each GAHnix node you wish to add to the system
5. Restart the NFS service: /etc/init.d/nfs restart
3. Setting up the application software for use by each GAHnix node. Installing the Distributed Folding client as an example:
1. Download and install the Distributed Folding client (gcc version), install the software in the directory: /exports/cruncher1/distribfold
2. Ensure that the software binary is exectuable. If not, set the executable bit: chmod +x program_name

Preparing the Linux Workstation

To prepare GAHnix for remote connections using SSH, you must first setup an SSH keypair. The private key is stored on your Linux SSH workstation, while the public key is copied to the GAHnix boot floppy.

On the Linux SSH workstation, open a terminal window and as root do the following:

1. Creating a public/private SSH key pair (you probably want to do this once only)
1. Generate the SSH keys: ssh-keygen -d
The private key is stored on your Linux SSH workstation (in /root/.ssh/id_dsa), the public key is created as /root/.ssh/id_dsa.pub and is later copied to the GAHnix boot disk, once the boot disk has been created (see the next section titled "Preparing the GAHnix Nodes").
2. Adding the hostname of each GAHnix node to /etc/hosts
1. Add the IP/hostname of the GAHnix node to /etc/hosts, for example:
   

       192.168.0.10 cruncher1

Preparing the GAHnix Nodes

The following installation process is performed on the Linux workstation. When editing GAHnix configuration files, ensure that each line containing text is terminated by a carriage return. The following configuration files are pre-configured, you must modify them to suit your application.

1. Building a GAHnix boot floppy for each node
1. Download the GAHnix floppy image
2. Insert a blank 1.44MB 3.5" floppy disk into the floppy drive (fd0).
3. Open a terminal window, change to the directory containing gahnix.img
4. Type: dd if=gahnix.img of=/dev/fd0
   (Substitute /dev/fd0 with your floppy device if it is not fd0)
2. Configuring the GAHnix boot floppy
1. Mount the boot floppy on the installation workstation using: mount -t vfat /dev/fd0 /mnt/floppy
2. Edit /mnt/floppy/tux/config/eth0 and define the IP address and network mask for the GAHnix node, for example:
   

       192.168.0.10 255.255.255.0

3. Edit /mnt/floppy/tux/config/gateway and define the IP address of the gateway machine or router, used to access the internet, for example:
   

       192.168.0.1

4. Edit /mnt/floppy/tux/config/dns and define the IP address of the DNS machine.
   This would be typically be your gateway machine (assuming that it runs as a caching name server) or it may be the IP address of your ISP's DNS machine. For example:
   

       192.168.0.1

5. Edit /mnt/floppy/tux/config/server and define the IP adress and path of your central HTTP server, for example:
   

       http://192.168.0.1/gahnix/

6. Edit /mnt/floppy/tux/config/hostname and define the host name for the GAHnix node, for example
   

       cruncher1

7. Edit /mnt/floppy/tux/init/last and setup the application NFS mount for this node, for example:
   

       mount -o nolock 192.168.0.1:/exports/cruncher1 /mnt

8. And also setup the temporary directory NFS mount for this node, for example:
   

       mount -o nolock 192.168.0.1:/exports/cruncher1/tmp /tmp

9. Unmount the floppy drive: umount /mnt/floppy
3. Loading the SSH public key onto each GAHnix boot floppy
   To prepare GAHnix for remote connections using SSH, you must have first generated a SSH keypair, as covered in the previous section titled "Preparing the Linux Workstation". We now copy the public key to the GAHnix boot disk, open a terminal window on the SSH Workstation and as root do the following:
1. Mount the boot floppy on the installation workstation using: mount -t vfat /dev/fd0 /mnt/floppy
2. Copy the public key to the GAHnix boot floppy: cp /root/.ssh/id_dsa.pub /mnt/floppy/tux/pkg/opensshd/keys
3. Unmount the floppy drive: umount /mnt/floppy

Testing a GAHnix Node

1. Insert the GAHnix boot floppy into a suitable node machine
2. Ensure the machine is connected to the central server
3. Power up the GAHnix node
4. The GAHnix system should now boot. Ensure that the modules are loaded fromt he central server, this can be confirmed at boot time by observing the bootup messages
5. When the system is ready, hit you should be greeted with a bash prompt
6. Check that the NFS mounts are mounted: mount
   You should see the following:

       root@cruncher1> mount

       192.168.0.1:/exports/cruncher1 on /mnt type nfs (rw,nolock,addr=192.168.0.1)

       192.168.0.1:/exports/cruncher1/tmp on /tmp type nfs (rw,nolock,addr=192.168.0.1)

7. Check the SSH login, as root on the SSH workstation, type: ssh -2 -l root cruncher1
   You should be greeted with an SSH session from cruncher1 like so:

   ************************************** 

   * Welcome to GAHnix!                 *

   *                                    *

   * Ctl-D to close this SSH session.   *

   **************************************

   root@cruncher1 

Using GAHnix

General

GAHnix does not use login authorisation, and there is one one user - root. A total of 4 consoles are provided, each may be accessed with Alt-F1 to Alt-F4. Most of the standard Linux command line utilities are available such as ls, cd, cp, mv, rm, ps, grep, vi, more, chmod, chown, grep, cat, cut, date, dd, mount, umount, ln, pwd, tail, head, telnet, sort, tar etc.

Accessing a GAHnix node using SSH is quite straight forward. From a Linux or Windows machine, type: ssh -2 -l root node_name where 'node_name' is the host name of the GAHnix node. It is important that SSH seesions are closed by pressing Ctl-D and not by closing the X-Windows window, otherwise the SSH daemon on the GAHnix node will not be killed.

GAHnix should run flawlessly and not require regular maintenance. Should you wish to shutdown or reboot a GAHnix node, use poweroff or reboot.

Configuration

The GAHnix configuration files are stored in /etc/tux/config. You may edit these files using vi, however as the GAHnix filesystem resides in RAM disk, to keep any changes over a re-boot, you must save the configuration to disk using savecfg. Savecfg is a Linux bash script that writes the /etc/tux configuration directories back to the floppy drive.

The NFS mounts are mounted into /mnt by default, as determined by the boot-time script in /etc/tux/init/last. These mounts may be modified as required. You can modify configuration files in /etc/tux at any time, just be sure to save the configuration to disk using savecfg. Alternately, the floppy disk may be edited using a DOS or Windows machine, simply load the disk into a DOS drive and edit the files in A:\tux. This is the same as the /etc/tux directory under Linux.

You may set application's to run at startup by adding them to /etc/tux/init/last, but ensure you add them to the end of the file, after the remote NFS mounts have been mounted. For example, assuming you have the rc5 client mounted in /mnt/dnet your /etc/tux/init/last would look something like this:

    #   

    # Here is where you can add any last-minute commands/scripts 

    # you want executed before consoles' are opened up   

    #                

    echo "Tweaking libraries"    

    ln -s /usr/lib/libncurses.so.5 /lib/libncurses.so.4   

    ldconfig       

    echo "Executing [last]"  

    echo "Mounting NFS mount point in /mnt"  

    mount -o nolock 192.168.0.1:/exports/kochanski /mnt    

    echo "Mounting NFS mount point in /tmp"   

    mount -o nolock 192.168.0.1:/exports/kochanski/tmp /tmp 

    cd /mnt/dnet    

    ./dnetc    

The GAHnix boot floppy may be mounted under GAHnix, using fmount, this will mount the floppy into /floppy. To un-mount the floppy, use fumount.

Config file summary

Config File	Description	Example
/etc/tux/config/hostname	GAHnix node hostname	cruncher1
/etc/tux/config/eth0	GAHnix node IP address/network mask	192.168.0.10 255.255.255.0
/etc/tux/config/gateway	The IP address of your Internet Gateway/Router	192.168.0.1
/etc/tux/config/dns	The IP address of your DNS server	192.168.0.1
/etc/tux/config/server	The URL to your HTTP server (GAHnix packages)	http://192.168.0.1/gahnix/
/etc/tux/init/last	Boot time script, executed once the system is up. Also contains the NFS mount commands.	(Add your program' to be run at boot time here) mount -o nolock 192.168.0.1:/exports/cruncher1 /mnt

Backing-up boot floppies

You can back-up a GAHnix boot floppy to a Linux workstation, allowing you to make new boot disks with your configuration settings. Lets say you have a GAHnix boot floppy that is configured correctly, and you wish to back-up this floppy to your Linux workstation and later use this backup to make new GAHnix boot floppies, simply follow these steps:-

1. Insert the GAHnix boot floppy disk into the floppy drive (fd0) of the Linux workstation.
2. Open a terminal window, change to the directory that you wish to stoore your backup in.
3. Type: dd if=/dev/fd0 of=my_gahnix_boot_disk.img
   (Substitute /dev/fd0 with your floppy device if it is not fd0, my_gahnix_boot_disk.img may be any name you choose.)

This will make a disk-image of the boot floppy, called my_gahnix_boot_disk.img on your Linux workstation. You may make new GAHnix boot floppies from this image, like so:-

1. Insert a blank 1.44MB 3.5" floppy disk into the floppy drive (fd0).
2. Open a terminal window, change to the directory containing my_gahnix_boot_disk.img
3. Type: dd if=my_gahnix_boot_disk.img of=/dev/fd0
   (Substitute /dev/fd0 with your floppy device if it is not fd0)

This method is very convinient, as your GAHnix boot disk will all generally have the same dns, server & gateway settings. Only the eth0 & hostname files require modifying from one node to the the next.

Cron

GAHnix includes a cron daemon. The crontab is configured at boot-time using /etc/tux/config/crontab. You may add your own cron tasks by adding them to this configuration file, but remember to save your configuration using savecfg.

When adding new cron tasks to a running GAHnix system, you must add the task to both the running crontab in /var/spool/cron/crontabs/root (alternately you may edit the running crontab using crontab -e) as well as modifying the boot-time crontab as outlined in the previous paragraph above. Failure to modify /etc/tux/config/crontab will result in the loss of crontab modifications over a reboot.

TuxTime

GAHnix includes the version 0.2.0 TuxTime client in /bin/tuxtime.bin. You may add the TuxTime client to your crontab by adding the following to /etc/tux/config/crontab (and also to /var/spool/cron/crontab/root if you dont wish to re-boot the system):

    0 * * * * tuxtime.bin username password 12345 > /dev/null

Where:
0 * * * * runs the TuxTime client once per hour.
username is your TuxTime account name.
password is your account password.
12345 is the TuxTime ID of the GAHnix computer.

CopyRight Information

GAHnix
A small compact Linux distribution based on Trinux, for disk-less network booting nodes.
Copyright (c) 2001, 2002 by Wayne Osborn
aka dna of Ninja Micros/Team 3DHQ/Team Picard
Released under the LMAO Public License

GAHnix is free software. This means that it's yours to try, for free non-commercial use, forever.
If you enjoy the product, please send in a donation to help support further development and web-server costs.