Difference between revisions of "Outreach Program Projects"

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|Project=XL to XCP VM motion
|Contact=[mailto:ian.campbell@citrix.com Ian Campbell]
|Desc=Currently [[XL|xl]] (the toolstack supplied alongside Xen) and [[XAPI|xapi]] (the XCP toolstack) have very different concepts about domain configuration, disk image storage etc. In the XCP model domain configuration is persistent and stored in a data base while under xl domain configuration is written in configuration files. Likewise disk images are stored as VDIs in Storage Repositories while under xl disk images are simply files or devices in the dom0 filesystem. For more information on xl see [[XL]]. For more information on XCP see [[XCP Overview]].
This project is to produce one or more command-line tools which support migrating VMs between these toolstacks.
One tool should be provided which takes an xl configuration file and details of an XCP pool. Using the XenAPI XML/RPC interface It should create a VM in the pool with a close approximation of the same configuration and stream the configured disk image into a selected Storage Repository.
A second tool should be provided which performs the opposite operation, i.e. give a reference to a VM residing in an XCP pool it should produce an XL compatible configuration file and stream the disk image(s) our of Xapi into a suitable format.
These tools could be reasonably bundled as part of either toolstack and by implication could be written in either C, Ocaml or some other suitable language.
The tool need not operate on a live VM but that could be considered a stretch goal.
An acceptable alternative to the proposed implementation would be to implement a tool which converts between a commonly used VM container format which is supported by XCP (perhaps [http://en.wikipedia.org/wiki/Open_Virtualization_Format OVF] or similar) and the xl toolstack configuration file and disk image formats.

Revision as of 14:11, 17 September 2015

Icon Info.png The links below need to be updated before September 28th 2015

The Xen Project is a Linux Foundation collaborative project that develops the

  • Xen Hypervisor (for x86 and ARM)
  • The XAPI toolstack
  • Mirage OS

The project also has excellent relationships with its upstreams (Linux Kernel, the BSDs, QEMU and other projects) and upstreams such as Linux distributions. This is reflected in the project list, which contains many interesting cross-project development projects for applicants.

Finding a project that fits you

This page lists Xen Project development projects for Outreachy (formerly the Outreach Program for Women) that can be picked up by anyone! If you're interesting in hacking Xen Project code and want to become a part of our friendly developer community this is the place to start! Ready for the challenge?

To work on a project:

  • Find a project that looks interesting (or a bug if you want to start with something simple)
  • Send an email to the relevant mailing list (see Developer Mailing Lists) and let us know if you are interested in starting to work or applying on a specific project.
  • Post your ideas, questions, RFCs to the relevant mailing list sooner than later so you can get comments and feedback.

You have your own project idea: no problem!

  • If you have your own project idea, outline what you are trying to do on the mailing list. If you know the right list, post your project idea on mailing list. Failing that post on xen-devel and we can redirect you to the right list. Make sure you add OPW 2014 to the subject line.

It is a good idea to ...
The Xen Project has also participated in the Gnome Outreach Program for Women (OPW) and Google Summer of Code (GSoC) in the past. One of the things we learned by participating in these programs is that you will be more successful, happier and get more out of participating in internship programs, if you do a bit of prep-work before writing an application. Here is some stuff you can do:

  • Contact your mentor early and get to know him or her
  • Start hanging out on our IRC channel. You can use the #xen-opw IRC channel on freenode.net for now
  • You may want to ask the mentor for a couple of small bitesize work-items (such as reviewing someones patch, a bitesize bug, ...) and start communicating on the relevant mailing list. That helps you become familiar with our development process, the mentor and other community members and will help you chose the right project and help you decide whether the Xen project is for you.
  • Note that quite a few Xen maintainers used to be GSoC participants once. Feel free to ask community dot manager at xenproject dot org to put you in touch with them if you have questions about their experience.
  • Any work you submit before applying for a project should be based on xen-unstable development tree, if the project is Xen Hypervisor and/or tools related. Linux kernel related patches should be based on upstream kernel.org Linux git tree (latest version). XAPI and Mirage OS patches should be based on the right codeline too. Check out the navigation by audience section on the left to find resources.

More resources

Quick links to changelogs of the various Xen related repositories/trees: Please see XenRepositories wiki page!

Before to submit patches, please look at Submitting Xen Patches wiki page and the relevant Xen Project team page. This will contain more information.

If you have new ideas, suggestions or development plans let us know and we'll update this list!

Aspiring Participants

  • Please contact the mentor and CC the most appropriate mailing list
  • Get a bite-size task from the mentor before the application starts
  • If you feel comfortable with an idea, please put your name to an idea using the following format
|Review=(delete as addressed)
* {{Comment|~~~~:}} I am interested in this idea ... 
                    (note that you may also want to link to the e-mail thread with the mentor)
  • You will need to request write access to the wiki by filling out this form

Outreach Program Project Ideas

List of peer reviewed Projects

Domain support (PVOPS and Linux)

Enabling the 9P File System transport as a paravirt device

Date of insert: 01/20/2014; Verified: 02/13/2015; GSoC: Yes
Technical contact: Wei Liu <wei.liu2@citrix.com> Julien Grall <julien.grall@citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: High
Skills Needed: Required skills include knowledge of kernel hacking, file system internals. Desired skills include: understanding of Xen PV driver structure, and VirtIO.
Description: VirtIO provides a 9P FS transport, which is essentially a paravirt file system device. VMs can mount arbitrary file system hierarchies exposed by the backend. The 9P FS specification has been around for a while, while the VirtIO transport is relatively new. The project would consist of implementing a classic Xen front/back pv driver pair to provide a transport for the 9P FS Protocol.
Outcomes: Expected outcome:
  • LKML patches for front and back end drivers.
  • In particular, domain should be able to boot from the 9P FS.

Xen Hypervisor Userspace Tools

CPU/RAM/PCI diagram tool

Date of insert: 01/30/2014; Verified: Not updated in 2020; GSoC: yes
Technical contact: Andrew Cooper <andrew.cooper3@citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Moderate, to Extremely Difficult (depending on which area of the problem you choose to tackle)
Skills Needed: Understanding of PC server hardware, Understanding of ACPI/SMBios tables, Linux scripting or kernel hacking (depending on which area of the problem you choose to tackle)
Description: It is often useful in debugging kernel, hypervisor or performance problems to understand the bus topology of a server. This project will create a layout diagram for a server automatically using data from ACPI Tables, SMBios Tables, lspci output etc. This tool would be useful in general Linux environments including Xen and KVM based virtualisation systems. There are many avenues for extension such as labelling relevant hardware errata, performing bus throughput calculations etc.
Outcomes: A tool is created that can either run on a live Linux system or offline using captured data to produce a graphical representation of the hardware topology of the system including bus topology, hardware device locations, memory bank locations, etc. The tool would be submitted to a suitable open-source project such as the Xen hypervisor project or XCP.

KDD (Windows Debugger Stub) enhancements

Date of insert: 01/30/2014; Verified: 09/17/2015; GSoC: yes
Technical contact: Paul Durrant <paul.durrant@citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Medium
Skills Needed: C, Kernel Debuggers, Xen, Windows
Description: kdd is a Windows Debugger Stub for Xen hypervisor. It is OSS found under http://xenbits.xen.org/gitweb/?p=xen.git;a=tree;f=tools/debugger/kdd;h=fd82789a678fb8060cc74ebbe0a04dc58309d6d7;hb=refs/heads/master

kdd allows you to debug a running Windows virtual machine on Xen using standard Windows kernel debugging tools like WinDbg. kdd is an external debugger stub for the windows kernel. Windows can be debugged without enabling the debugger stub inside windows kernel by using kdd. This is important for debugging hard to reproduce problems on Windows virtual machines that may not have debugging enabled.

Expected Results:

  1. Add support for Windows 8.1 and 10 (x86, x64) to kdd
  2. Add support for Windows Server 2012 to kdd
  3. Enhance kdd to allow WinDbg to write out usable Windows memory dumps (via .dump debugger extension) for all supported versions
  4. Produce a user guide for kdd on Xen wiki page
Nice to have: Allow kdd to operate on a Windows domain checkpoint file (output of xl save for e.g.)
Outcomes: Code is submitted to xen-devel@xen.org for inclusion in the xen-unstable project.

Mirage OS

Create a tiny VM for easy load testing

Date of insert: 01/30/2014; Verified: Not updated in 2020; GSoC: yes
Technical contact: Dave Scott <dave.scott@eu.citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Medium
Skills Needed: OCaml
Description: The Mirage OS framework (see http://xenproject.org/developers/teams/mirage-os.html, http://www.openmirage.org/) can be used to create tiny 'unikernels': entire software stacks which run directly on the Xen hypervisor. These VMs have such a small memory footprint (16 MiB or less) that many of them can be run even on relatively small hosts. The goal of this project is to create a specific unikernel that can be configured to generate a specific I/O pattern, and to create configurations that mimic the boot sequence of Linux and Windows guests. The resulting unikernel will then enable cheap system load testing.

The first task is to generate an I/O trace from a VM. For this we could use 'xen-disk', a userspace Mirage application which acts as a block backend for xen guests (see http://openmirage.org/wiki/xen-synthesize-virtual-disk). Following the wiki instructions we could modify a 'file' backend to log the request timestamps, offsets, buffer lengths.

The second task is to create a simple kernel based on one of the MirageOS examples (see http://github.com/mirage/mirage-skeleton). The 'block' example shows how reads and writes are done. The previously-generated log could be statically compiled into the kernel and executed to generate load.
Outcomes: 1. a repository containing an 'unikernel' (see http://github.com/mirage/mirage-skeleton) 2. at least 2 I/O traces, one for Windows boot and one for Linux boot (any version)

Fuzz testing Xen with Mirage

Date of insert: 28/11/2013; Verified: Not updated in 2020; GSoC: yes
Technical contact: Anil Madhavapeddy <anil@recoil.org>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: medium
Skills Needed: OCaml, Xen
Description: Mirage OS (see http://xenproject.org/developers/teams/mirage-os.html, http://www.openmirage.org/) is a type-safe unikernel written in OCaml which generates highly specialised "appliance" VMs that run directly on Xen without requiring an intervening guest kernel. We would like to use the Mirage/Xen libraries to fuzz test all levels of a typical cloud toolstack. Mirage has low-level bindings for Xen hypercalls, mid-level bindings for domain management, and high-level bindings to XCP for cluster management. This project would build a QuickCheck-style fuzzing mechanism that would perform millions of random operations against a real cluster, and identify bugs with useful backtraces.

The first task would be to become familiar with a specification-based testing tool like Kaputt (see http://kaputt.x9c.fr/). The second task would be to choose an interface for testing; perhaps one of the hypercall ones.

Outcomes: 1. a repo containing a fuzz testing tool; 2. some unexpected behaviour with a backtrace (NB it's not required that we find a critical bug, we just need to show the approach works)

Mirage OS web stack testing

Date of insert: 25/02/2014; Verified: Not updated in 2020; GSoC: yes
Technical contact: Anil Madhavapeddy <anil@recoil.org>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: medium
Skills Needed: OCaml, shell scripting
Description: MirageOS has an emerging web toolstack that's broken up as a series of libraries -- for example, Cohttp, Uri, Cow, Ipaddr, RSS and Cowabloga. This project will get you familiar with them by building a protocol testing framework that can generate traffic using off-the-shelf tools such as httperf, and evaluate the results vs applications such as Apache or Nginx.
Outcomes: 1. a test harness for HTTP; 2. some results of the evaluation using the test harness

List of projects that need more work

Domain support (PVOPS and Linux)

Implement Xen PVSCSI support in xl/libxl toolstack

Date of insert: 01/12/2012; Verified: Not updated in 2020; GSoC: Yes
Technical contact: Pasi Karkkainen <pasik@iki.fi>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Unknown
Skills Needed: Unknown
Description: xl/libxl does not currently support Xen PVSCSI functionality. Port the feature from xm/xend to xl/libxl. Necessary operations include:
  • Task 1: Implement PVSCSI in xl/libxl, make it functionally equivalent to xm/xend.
  • Send to xen-devel mailinglist for review, comments.
  • Fix any upcoming issues.
  • Repeat until merged to xen-unstable.
  • See above for PVSCSI drivers for dom0/domU.
  • Xen PVSCSI supports both PV domUs and HVM guests with PV drivers.
  • More info: http://wiki.xen.org/xenwiki/XenPVSCSI
Pictogram voting comment 15px.png Lars.kurth 14:14, 23 January 2013 (UTC): Should be suitable, but desc needs. Rate in terms of challenges, size and skill. Also kernel functionality is not yet upstreamed. Maybe Suse kernel.
Outcomes: Not specified, project outcomes

Xen Hypervisor

Introducing PowerClamp-like driver for Xen

Date of insert: 01/22/2013; Verified: Not updated in 2020; GSoC: Yes
Technical contact: George Dunlap <george.dunlap@eu.citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Unknown
Skills Needed: Unknown
Description: PowerClamp was introduced to Linux in late 2012 in order to allow users to set a system-wide maximum

power usage limit. This is particularly useful for data centers, where there may be a need to reduce power consumption based on availability of electricity or cooling. A more complete writeup is available at LWN.

These same arguments apply to Xen. The purpose of this project would be to implement a similar functionality in Xen, and to make it interface as well as possible with the Linux PowerClamp tools, so that the same tools could be used

for both. GSoC_2013#powerclamp-for-xen
Outcomes: Not specified, project outcomes

Xen Hypervisor Userspace Tools

Refactor Linux hotplug scripts

Date of insert: 15/11/2012; Verified: Not updated in 2020; GSoC: Yes
Technical contact: Roger Pau Monné <roger.pau@citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Unknown
Skills Needed: Unknown
Description: Current Linux hotplug scripts are all entangled, which makes them really difficult to understand or modify. The reason of hotplug scripts is to give end-users the chance to "easily" support different configuration for Xen devices.

Linux hotplug scripts should be analized, providing a good description of what each hotplug script is doing. After this, scripts should be cleaned, putting common pieces of code in shared files across all scripts. A Coding style should be applied to all of them when the refactoring is finished.

Outcomes: Not specified, project outcomes

Advanced Scheduling Parameters

Date of insert: 01/22/2013; Verified: Not updated in 2020; GSoC: Yes
Technical contact: George Dunlap <george.dunlap@eu.citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Unknown
Skills Needed: Unknown
Description: The credit scheduler provides a range of "knobs" to control guest behavior, including CPU weight and caps. However,

a number of users have requested the ability to encode more advanced scheduling logic. For instance, "Let this VM max out for 5 minutes out of any given hour; but after that, impose a cap of 20%, so that even if the system is idle he can't an unlimited amount of CPU power without paying for a higher level of service."

This is too coarse-grained to do inside the hypervisor; a user-space tool would be sufficient. The goal of this project would

be to come up with a good way for admins to support these kinds of complex policies in a simple and robust way.
Outcomes: Not specified, project outcomes

PCI Pass-through improvements

Allowing guests to boot with a passed-through GPU as the primary display

Date of insert: 01/22/2013; Verified: Not updated in 2020; GSoC: Yes
Technical contact: George Dunlap <george.dunlap@eu.citrix.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Unknown
Skills Needed: Unknown
Description: One of the primary drivers of Xen in the "consumer market" of the open-source world is the ability to

pass through GPUs to guests -- allowing people to run Linux as their main desktop but easily play games requiring proprietary operating systems without rebooting.

GPUs can be easily passed through to guests as secondary displays, but as of yet cannot be passed through as primary displays. The main reason is the lack of ability to load the VGA BIOS from the card into the guest.

The purpose of this project would be to allow HVM guests to load the physical card's VGA bios, so that the guest can boot with it as the primary display.

Outcomes: Not specified, project outcomes

Improve PCIe Advanced Error Reporting (AER) handling for passed-through devices

Date of insert: 03/04/2014; Verified: Not updated in 2020; GSoC: Yes
Technical contact: Matt Wilson <msw@amazon.com>
Mailing list/forum for project: xen-devel@
IRC channel for project: #xen-devel
Difficulty: Medium-High
Skills Needed: Understanding of PC server hardware, PCIe, C
Description: Today the xen-pciback driver handles an AER event for passed-through PCI devices. If the device is assigned to a PV guest, it uses xenstore to request a reset from xen-pcifront. If the device is assigned to a HVM guest, the toolstack is notified and is expected to take corrective action. The toolstack support for taking corrective action is only implemented in xend, not libxl. For HVM guests ideally, the AER event would be propagated into the guest through the device model (qemu) so that the driver inside the guest can take reset actions.
Outcomes: Patches for libxl, qemu, and perhaps xen-pciback posted


New Project Ideas

Please add new project ideas here, following

Conventions for Projects and Project Mentors

Rules and Advice for Adding Ideas

  • Be creative
  • Add projects into New Project Ideas or improve projects in Project Ideas that Need Review or more work through review comments.
  • Use the {{GSoC Project}} template to encode ideas on this page. Please read the Template Documentation before you do so.
  • Be specific: what do you want to be implemented; if at all possible provide an indication of size and complexity as described above to make it easier for an applicant to choose ideas
  • If you are willing to mentors those ideas, add your name and email to the idea.
  • Aspiring mentors should introduce themselves on the most appropriate Xen Project mailing list

Peer Review Goals

We strongly recommend and invite project proposers and project mentors to review each others proposals. When you review, please look out for

  • Can an intern get going and started with the information in the project description
  • Are any unstated assumptions in the proposal, is there undefined terminology, etc. in the proposal
  • Can the project completed in 3 months (assume that one month is needed for preparation)
  • Does the project meet Google Summer of Code goals, which are
    • Create and release open source code for the benefit of all
    • Inspire young developers to begin participating in open source development
    • Help open source projects identify and bring in new developers and committers
    • Provide interns the opportunity to do work related to their academic pursuits (think "flip bits, not burgers")
    • Give interns more exposure to real-world software development scenarios (e.g., distributed development, software licensing questions, mailing-list etiquette)

Peer Review Conventions

The {{GSoC Project}} template used to encode project listings, contains some review functionality. Please read the Template Documentation before you add a template, also please use the conventions below to make comments.

|Review=(delete as addressed)
* {{Comment|~~~~:}} Comment 1
* {{Comment|~~~~:}} Comment 2

Choosing Projects

We have a bi-weekly mentor meeting overlooked by our program management team, which are a core team of 2-3 mentors and a program administrator. This group will work with mentors to ensure that project proposals are of good quality and whether mentors are engaging with the program management team and particpants in the weeks before the application period ends.