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Adding New Nodes and Images

Memory Filesystem

A very powerful feature of Emulab is its ability to load custom OSes (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.

More information about downloading and localizing the MFSs can be found on the MFS Import page. If you are in the middle of installing a new Emulab, the installation process has already downloaded and localized the MFSs for you, but if need to update later (say, if your hardware does not boot and you need a new kernel from Utah), then you will want to look at the instructions on the MFS Import after downloading a new tarball.

Note that the current MFS tarball can always be found at

Standard Images

Utah also provides a number of Standard images to get you started. Starting with one of these images when installing a new testbed, is by far, the easiest way to go. Once you gain experience with your Emulab, you can think about trying to build your image from scratch. These images have fairly generic kernels and should boot on most hardware, but if you have problems, be sure to ask questions on the email list.

You can find Utah's standard images at Instructions on how to import one of these images into your Emulab is on the image import page. If you are in the middle of installing a new Emulab, an initial image was already downloaded for you.