Memory Filesystem and Generic Images
A very powerful feature of Emulab is its ability to load custom OSes or disk images to its nodes. In order to provide control over the testbed nodes, Emulab software uses network-booted, memory-filesystem-based FreeBSD systems (hereafter known as MFSes). Each node upon powering on will boot one of these images over PXE/tftp and check in with the Emulab control system. At this point the node may either remain in the MFS, boot an existing partition on its disk, or receive a new disk image from boss via the control network.
If you haven't already, download the latest
tftpboot MFS tarball and extract it to /tftpboot. From there,
follow the included instructions in the README file.
This will install the MFS images and add the appropriate entries into the database.
We will also provide you with a generic disk image tarball. This tarball will include a multi-OS "full disk" combo image and one or more auxiliary "single partition" images. The combo image is one which has both a FreeBSD partition and a Linux partition. By convention FreeBSD is in DOS partition #1 and Linux in DOS partition #2. You will need to customize both, as described later in Customizing the Generic Image.
We provide two versions of the generic disk image. The version you will need depends largely on the hardware in your testbed and what advanced Emulab features you might need. The choices are:
- FBSD62+FC6-GENERIC.ndz - Includes FreeBSD 6.2 and Fedora 6.
- FBSD410+RHL90-GENERIC.ndz - Includes FreeBSD 4.10 and Redhat 9.
Generally, you will want to use the former as your default image that disks are loaded with. The reason the second image is included at all is that it must be used for "virtual node" support, which right now is only available in our modified FreeBSD 4.10 kernel. Unfortunately, the 4.10 kernel, being more than 5 years old, doesn't run on all modern hardware, due to lack of drivers and/or buggy ACPI support. So you may be stuck without vnodes for awhile if your hardware is in the unsupported category. There is also a lesser dependency on FreeBSD 4.10 for the control net firewall support.
So, if you want/need vnodes or firewalls but your node hardware won't boot FreeBSD 4.10, contact us and we'll figure something out.
When you decide which image to use, login to the the web interface on boss and go into 'red dot' mode. From the 'Administration' tab, go to 'Edit Site Variables'. In this list of variables you will find one called 'general/default_imagename'. Click on the adjacent green button to modify it to FBSD62+FC6-STD or FBSD410+RHL90-STD, depending on which image you have chosen.
