PXEbhyve [FreeBSD WIKI]

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====== Adding PXE Support for FreeBSD Guests to bhyve ======
  * Student: Steven Douglas (sdouglas@freebsd.org)
  * Mentor: Rui Paulo

===== Project description =====

My project will add basic PXE support to bhyve for %%FreeBSD%% guests. Though PXE is the most accurate term to describe the idea, it is slightly misleading. My work will take place in bhyveload, the bhyve userspace loader, which is a fork of %%FreeBSD%%'s standard boot loader. I will add support for basic DHCP, and loading the kernel, loader.conf (boot time configuration), and modules from a remote TFTP server specified either in the DHCP “next-server” field, or in a bhyve tunable. Once the kernel and modules are loaded bhyve may simply start execution of the kernel as usual.

This project would be benefit bhyve users in a number of ways. First it would allow running a centralized kernel build across a host's %%FreeBSD%% virtual machines. If you run a custom kernel, only a single rebuild would be required. If you run the generic one, you only need to patch a single kernel. This project also opens the door to running VM's without virtual hard drives. It could also allow for using a previous GSOC project for PXE automated installations in bhyve.

The feature would make it possible to deliver a common set of kernels to all of the virtual machines across multiple bhyve instances as they boot. For example, if I had a "Web Server" and a "Database server", I could specify in DHCP that they require a different kernel or different modules loaded at boot. All my kernels are still in one place though, I don't have to rebuild the kernels on each bhyve host, just once on the TFTP server.

===== Approach to solving the problem =====

I think that the problem can be broken into its individual pieces fairly easily:

  * Successfull DHCP lease with access to "next-server" and "filename" 
  * Fetch loader.conf via TFTP
  * Fetch Kernel via TFTP
  * Fetch Modules via TFTP
  * Load everything into memory and pass the location of the kernel and modules to bhyve.

After these parts are working individually, I think it should be much easier to introduce it into bhyve.

===== Deliverables =====

The following features will be implemented:
  * Successfull PXE-like boot loading loader.conf, kernel, and modules via TFTP.
  * Alternative configuration file option to load from static next-server / filename without the need for DHCP.

If there is time:
  * Sucessfull PXE-like boot loading loader.conf, kernel, and moduels via HTTP.

===== Milestones =====

Here are my milestones for the project. I hope to get alot done in the hackers lounge at BSDCan.

  * (May 25: Start of Coding)
  * June 8: Successful DHCP Leaseing
  * (June 9-13: BSDCan)
  * June 14: Successful loader.conf via TFTP
  * June 18: Successfull kernel via TFTP
  * July 23: Successfull modules via TFTP
  * (June 26 - July 3: Midterm Evaluations)
  * July 10: First successful complete boot
  * July 29: First successful complet http boot
  * August 5: Code cleaned up
  * August 15: Documentation finished, Wiki up to date
  * (August 17: Coding stops (soft%%))%%
  * (August 21: Coding stops (hard%%))%%

===== Test Plan =====

It is fairly easy to test the final product. When we can can boot a %%FreeBSD%% VM in bhyve via a tftp loader.conf / kernel / modules, it is working.

This section is still in flux.

===== The Code =====

https://socsvn.freebsd.org/socsvn/soc2015/sdouglas/

===== Useful links =====