Xen Document Days/TODO

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Go back to Xen Project Document Days

Requested Documentation

Feel free to comment on items using the following convention: * {{Comment|~~~~:}} your comment Feel free to add new workitems using the following convention: ==== Workitem ==== ~~~~: work-item description

(SUGGESTED FOR MAY 28, 2014) Performance-related Documentation

The documentation on Performance Tuning seems thin, given the importance of the subject:

• Category:Performance Lists the Performance docs currently available.
• Network_Throughput_and_Performance_Guide Has lots of interesting information, but it is oriented for XenServer/XCP. This needs to be recast as a true Xen Project document.
• Tuning_Xen_for_Performance Is potentially the most important document, but it has only a few topics and not that many details. There is some discussion about this page in section 3.12

(IMPORTANT) Linux Distros

It seems that the list of Linux Distros which support Xen is a lot larger than listed on this wiki.

• Funtoo
• Mageia
• Univention Corporate Server (UCS)
• Are there others?

The following pages need updating and new categories need to be created (these pages are used as reference by new users so they are extremely important to keep up to date!):

• Dom0_Kernels_for_Xen
• DomU_Support_for_Xen << REALLY IMPORTANT!
• Template:Distro_Resources
• Add categories

In progress (some just need double checking whether finished)

Draft a list of Questions for a User Survey

• Lars.kurth 10:09, 30 April 2014 (UTC) : See Xen Project User Survey

Restructure XCP Related Categories

NOTE: XCP is about to be transitioned to a new home, so it is important that we make sure the XAPI content remains after XCP goes. Correctly tagging items for XAPI is essential. [April 30, 2014]

• This is executing the proposal http://lists.xenproject.org/archives/html/xen-api/2013-06/msg00109.html [Proposal for input] Disentangling XAPI, XAPI packages and XCP on wiki.xenproject.org]. In a nutshell:
• Category XCP : only use for content specific to the XCP ISO

Latest revision Your text

• New Category XAPI Project : this is basically a category for developers
• New Category XAPI Users : this is basically for users of XAPI, XAPI packages in distro and other flavours of XAPI (e.g. XCP ISO when not specific to the ISO)
• Move content into those locations

Easy tasks for Beginners

You may want to read Wiki Help if you do not have an account.

Migrate useful blog posts to wiki

Sift through blog.xenproject.org and copy useful posts to wiki. This will mainly be a reformatting exercise. Before you copy an article, perform a search on the wiki (headline or key word) to see whether the post exists already. If in doubt, ask on the IRC channel.

Fix articles that need attention

• Category:Contains_Needs_Formatting - Pages that need formatting
• Category:Contains_Needs_Action - Pages that need fixing. Go through these, and if you get stuck ask people on the IRC channel for help, or go to the next page.
• Category:Contains_TODO - Pages that have a TODO item on the page. Go through these, and if you get stuck ask people on the IRC channel for help, or go to the next page.

Review Categorization

• Sometimes new pages on the wiki are not created with categories. You can find these by going to Special:UncategorizedPages. Documentation about which category is used where can be found in Categories for Authors. If in doubt ask on IRC.

Pages With Comments or Improvement Suggestions

• We ask users to highlight issues using talk pages, following the conventions outlined in Help:Talk Pages. Comments made using these conventions can be identified using the Category:Pages with comments.

Missing Pages

• Special:WantedPages - You can find missing pages by going to this link. There are several courses of actoin that can be taken:
  • The page is needed : Add {{TODO|With a comment}} to the top of the page
  • The page is not needed : Remove the reference to the page (follow the link in the bracket besides the page)
  • Note that the list of Wanted pages contains lots of needed translations and categories, which you can ignore
  • If in doubt, ask for help on the IRC channel

 Double-p 09:55, 25 February 2013 (UTC): There are a gazillion Template-Whatever including a TODO, really needed?  Lars.kurth 17:40, 25 March 2013 (UTC): See #Special:WantedPages_broken

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Xen : Open work items

UEFI Secure Boot

Write a document on how to sign the xen binary for UEFI Secure Boot. Potential reference here: Dealing With Secure Boot

Documentation on lib(xen)vchan

The header has some stuff, but a more complete guide would be useful.

The usage of the example code is also not documented. http://lists.xen.org/archives/html/xen-users/2014-01/msg00162.html has some (incomplete) info.

Manpages for xe command

Write manpages for xe and its 430 subcommands.

• A team led by Grant McWilliams and including Matthew Spah, Lisa Nguyen and Mike Webber is currently working on documenting the xe command and will continue to do so until completed. Moving the source repo to xen-org has been [proposed].
• As of September 2013, the Xenapi Admin Project team is currently automating the manpage creation process for all xe subcommands.

Describe the different ways, and necessary components, to create PVs using xl

Raised by mail by Matthias Blankenhaus (who is prepared to take the lead, but needs help): This document would describe the different ways, and necessary components that each way requires, to create PVs using xl. Right now there are at least the following cases:

• loopbacked vhds
  • single partition format
  • disk format
• qemu backed vhds
  • qcow / qcow2
• LVS backed image

This is not a complete list. Also the mileage of each case differs depending on the kernel features enabled in dom0/domu and also depending on the Xen version. Furthermore, certain format require additional infrastructure like the tap device.

All in all, this a complex topic that needs clarification. Doing this based on the lowest common denominator, xl, would clarify many things. In addition, baseline performance data on all of the above would help a great deal. Matthias volunteered to run the majority of needed perf tests

Review and Update: xenpm usage recommendations

There is Xen power management and Xenpm command which may all be outdated. These should probably be reviewed and updated.

HOWTO : using xm trigger to poweroff or firing off NMIs

Howto on using xm trigger to poweroff or firing off NMIs.

HOWTO: Chain pypxeboot and pygrub

How to chain pypxeboot and pygrub

•  Lars.kurth 10:35, 27 March 2012 (UTC): Is pypxeboot popular at all?
•  Fheigl: I added that. It is somewhat common, OVM 2 and OVM 3 rely on it for PXE installs. I'm not sure if xenpvnetboot is the same, or works. The use case is "you want to use the same installation server for Xen VMs and phys. servers. You want to be able to reinstall them based on PXE reply.
•  Fheigl: There is documentation for pypxeboot, but there is no (afaik) documentation for how pygrub is used as a fallback loader. We wasted many days just to get some hack that can't even load a newer kernel. Which sucks, in the end you spend more time/money making PV PXE boot work than you save by using virtualized servers.
•  Fheigl: How could it be popular given the state of documentation. <= Key issue to the left of this sentence.
•  Lars.kurth 16:03, 19 September 2012 (UTC): wondering whether this video contains what is needed

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Visually distinguish Xen, XAPI, MirageOS and Community Documentation better

 Lars.kurth 15:32, 28 January 2013 (UTC): Users are getting confused when looking at wiki pages. If there was a visual way to distinguish Xen, XCP and Other content better, this would help. We could use colors and skinning when it comes to various elements, as well as masocts/logos:

• For example: Help:Contents has a different feel (and colour scheme)
• This could be replicated in trail boxes and other elements
• We can also use mascots (note we don't have an XCP mascot)

But first, I need to investigate what is possible.

 Lars.kurth 16:14, 28 January 2013 (UTC): Looks as if the only way this can be done is via Custom Namespaces. The only way to do this properly is to

• Have different namespaces for Xen, XCP, ... and Community stuff and keep all the common stuff in Xen
• The name spaces could then be styled differently, for example the Help namespace includes the ns-12 style into the body attributes, whereas the Main (default) namespace uses the ns-14 style.
• Custom namespaces can be created by changing the config and are linked to custom styles
• The styles are then defined in MediaWiki:Common.css

Implications of using custom namespaces:

• Search: Pages in a custom namespace do not show up in default search results. So if we had a custom XCP namespace, it would mean that search results for XCP would not show up. One would need to go to Advanced Search and select XCP
• Rename: Renaming pages is possible and as straightforward as renaming pages
• Xen Namespace: The Xen namespace exists already, this may need to be renamed
• Categories and Namespaces: Categories cross namespaces. In other words, Category:XXX would go across all namespaces. As an example, see Category:Wiki_Management

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Mediwiki Issues

Special:WantedPages broken

Issue 1: Pages that need translation are spamming the list

• Solution: fix language templates and mark with {{Stub translation}}
•  Lars.kurth 16:48, 28 January 2013 (UTC): There is something wrong with the language templates, essentially spamming the wanted pages. Do ignore these instructions until fixed.
•  Lars.kurth 23:28, 11 February 2013 (UTC): Fixed language template issues by removing most languages from the templates
•  Lars.kurth 18:03, 25 March 2013 (UTC): Started marking pages with {{Stub translation}}

Issue 2: Missing templates are spamming the list

• Solution: mark missing templates with {{Undefined Template}}
•  Lars.kurth 17:27, 25 March 2013 (UTC): Started marking all missing templates with {{Undefined Template}}

Issue 3: Missing categories are spamming the list

• Solution: mark with {{Stub category}}
•  Lars.kurth 18:03, 25 March 2013 (UTC): Started marking pages with {{Stub category}}

Categories & Indexes

•  Lars.kurth 13:54, 29 January 2013 (UTC): Combined categories such as list all XCP FAQs have been asked for sevceral times
• Investigate plug-ins

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Developer Docs

Docs that need attention or are missing

• Make XAPI docs (built from source) available on xen.org
• PVOPS portal on xen.org - Konrad volunteered
• some more xenstore docs (i.e. recent python bindings that were sent to the -users list
• Using libxenstat python bindings (imo they're broken)
• More PV protocol docs (see recent patches to blkif.h for example)
• Document xenstore paths used by guests and toolstack etc
  •  Ijc 16:10, 26 November 2012 (UTC): This is now in tree: http://xenbits.xen.org/docs/unstable/misc/xenstore-paths.html

Done Recently

Xen 4.4 Documentation

Need to flesh out Xen_4.4_Acknowledgements

Xen 4.3 / 4.4 Documentation : Spice Config Example for upstream QEMU

Take this thread and convert into an Example

 Lars.kurth 16:56, 9 April 2014 (UTC) Created SPICE_support_in_Xen for now

Update Xen Project Repositories

Xen Project Repositories references Xen 4.2 as the latest.

 Rcpavlicek 23:59, 27 January 2014 (UTC): Updated reference to 4.3, but needs a developer to verify that nothing else is needed.

 Lars.kurth 12:02, 2 April 2014 (UTC) This looks fine

Would be useful to also talk about qemu and other repos (e.g. seabios, ovmf) and the branches they use.

For qemu see http://lists.xen.org/archives/html/xen-users/2014-01/msg00049.html

 Ijc 15:59, 27 January 2014 (UTC): Updated it a bit, now links to more of the repos, but could do with some more work.

(IMPORTANT) XenAPI OpenStack Documentation

See related blueprint

•  Lars.kurth 08:13, 1 April 2014 (UTC) These seem to be handled by OpenStack. Removing from tracker

Bootloader & Console Configuration

Surprisingly little on these two topics, which should be added to Category:Host_Configuration

HOWTO : How to Set Up Nested Virtualization

See this thread

•  George Dunlap 31 March 2014 (UTC) Renamed "Xen Nested" to "Nested Virtualization in Xen", expanded intro, added categories.

Sidebar rendering in Chrome (broken again)

See [1]and (related) and (chrome bug description) - note that this has been fixed, then re-appeared

•  Lars.kurth 11:05, 31 March 2014 (UTC) Fixed by replacing KHTMLFixes.css on the server with an empty file. Before the change takes effect, clear the browser cache as per [2]

Xen 4.3 Release Notes

Need to flesh out Xen_4.3_Release_Notes (also see Xen_4.2_Release_Notes)

Xen 4.3 new features that need documentation

Need to make a HOWTO for openvswitch, link it to 4.3 test day and 4.3 release notes wiki pages.

• {{Comment|--Lars.kurth 16:04, 24 June 2013 (UTC)} These existed before. Linked to from [[Xen 4.3 Feature List]

Xen 4.3 Man Pages

Need to flesh out Xen_4.3_Man_Pages (also see Xen_4.2_Man_Pages)

Xen PV Architecture Documentation

Something like a SDM for Xen PV "processors".

Add pages to Category:Paravirtualised Architecture

• X86 Paravirtualised Memory Management
  • Needs OS specifics adding (e.g. Linux paravirt_ops)
• Grant Tables
• Event Channels
• I/O (blk in OK shape, net could catch up)
• ...
•  Lars.kurth 14:03, 29 January 2013 (UTC): Event Channel Internals was added
•  Lars.kurth 14:03, 29 January 2013 (UTC): Not sure how complete
•  --Lars.kurth 10:58, 24 June 2013 (UTC) Enough of this has been done

A Xen Performance Tuning Guide

• Which workloads work for which virt mode. Network considerations. NUMA. VCPU Pinning. Etc.
• Examples from the KVM world: Guest perf tuning, KVM options affecting performance, Comprehensive guide covering pinning, caching, memory, huge pages, etc.
•  Lars.kurth 19:50, 25 June 2012 (UTC): Work has been done on Tuning. Not sure whether more needs to be done.
•  Stefano 30 June 2012: The guide is in a decent state but I will keep improving it during the next doc days.
•  Lars.kurth 15:54, 19 September 2012 (UTC): Needs a quick sanity check for Xen 4.2
•  Lars.kurth 12:48, 22 January 2013 (UTC): Is this done?
•  --Lars.kurth 09:55, 24 June 2013 (UTC) Looks like it. But rename document
•  Rcpavlicek 16:26, 15 May 2014 (UTC): Are modifications or additions required here? Given the work done over the past couple of years, I expected this to be a longer document.
•  Ijc 09:22, 21 May 2014 (UTC): The stuff about VCPU pinning seems to be a bit misleading, it's not always the best thing to do. See e.g. http://lists.xen.org/archives/html/xen-users/2014-05/msg00163.html and in particular http://lists.xen.org/archives/html/xen-users/2014-05/msg00170.html.
  • In the referenced thread I said: "It does say "might" and "can" perhaps even those are a bit strong. Pinning is one tool in the performance tuning arsenal but it is very workload dependent on whether it will help or hurt (and it can be a lot in either direction).", which I think is accurate (and in any case the docs need to guide people better about when/whether to pin and what the up/downsides are etc).

Update Xen Release Features for Xen 4.3

Add Xen 4.3 to Xen_Release_Features and create Xen 4.3 Feature List (also see Xen 4.2 Feature List)

•  Lars.kurth 16:36, 29 April 2013 (UTC): Xen_Release_Features has been done based on Xen_Roadmap/4.3
•  Lars.kurth 16:41, 29 April 2013 (UTC): Created boilerplate for Xen 4.3 Feature List

Xen 4.3 Test Day Instructions

Need to flesh out Xen_4.3_RC1_test_instructions (also see XCP_1.6_test_instructions and Xen 4.2 RC2 test instructions)

•  Lars.kurth 16:36, 29 April 2013 (UTC): Has been done. ARM support needs adding. Also george had some ideas.

A Xen Security Guide

The different options in Xen for Security, trade-offs, how to set them up, how to test Xen for security and how to optimize for different scenarios

•  Lars.kurth 09:48, 27 March 2012 (UTC): Category:Security contains some security related docs
•  Lars.kurth 11:01, 4 April 2012 (UTC): It would be good if we could document a) XSM, b) Introspection API, c) Xen and SELinux in Dom0, d) Memory Access API (introduced in 4.1)
• User Docs that where migrating content would make sense and update such as (we can attach PDF's to the wiki now for starters, or we can use a conversion tool
  • http://bits.xensource.com/Xen/docs/user.pdf
•  Lars.kurth 15:59, 19 September 2012 (UTC): Some good articles came out of XenSummit NA (these can be built upon).
•  Lars.kurth 14:01, 29 January 2013 (UTC): Changes to Securing Xen & Driver Domain
•  Lars.kurth 14:01, 29 January 2013 (UTC): Got funding to document XSM; contract in place, but contractor is currently ill. This is the main outstanding issues.
•  --Lars.kurth 07:57, 24 June 2013 (UTC) --Lars.kurth 07:57, 24 June 2013 (UTC)Xen_Security_Modules_:_XSM-FLASK has been added and I added an overview and removed the TODO

Categories are not returned in search

•  Lars.kurth 13:54, 29 January 2013 (UTC): Categories do not get returned when searching. To find a category, once has to go to Advanced, click Categories and search for say security.
• We need to investigate whether there are better options for search (e.g. additional mediawiki plug-ins) or config options to change this behaviour
• IMPORTANT: This is actually a user preference. To change the default behavior go to Special:Preferences and tick Main, Xen, Help and Category. I will investigate defaults.
• FIX: See $wgNamespacesToBeSearchedDefault
•  Lars.kurth 13:59, 3 May 2013 (UTC): Fixed

Help create an htaccess file from xen_org to xenproject_org

We need to create a mapping file from xen_org to xenproject_org. The plan is to archive xen_org to somewhere like http://xenproject.org/archive and to decide which pages in xen_org go to the archives, and which to the new site. I will track information at xen_org to xenproject_org mapping.

Submitting Xen Patches

George Dunlap: Updated Submitting Xen Patches to have recommended workflow for git; moved Mercurial-specifc instructions to Submitting Xen Patches - mercurial .

Document release signing keys and fingerprints etc

We should publish the key ids and fingerprints somewhere.

•  Lars.kurth 13:54, 29 January 2013 (UTC): See OpenPGP keys

Better Statements on Compatibility

There seems to be some confusion in the wider Linxu community about XL/XM compatibility. Maybe some specific questions in an FAQ/the release notes. Also migration compatibility comes up often. Any articles related to compatibility should be listed in Category:Compatibility, which I am willing to clean up.

•  Anthony 14:33, 26 November 2012 (UTC): I add a bunch of pages to the category, and add few link in the category to upgrade from xend to xl.
•  Anthony 17:19, 26 November 2012 (UTC): I also redirect XL in Xen 4.2 to XL as they had both the same content minus few things.
•  Lars.kurth 12:48, 22 January 2013 (UTC): Is this done?
•  Ijc 16:39, 25 January 2013 (UTC): I think we also need to cover compatibility confusion about 3.x vs 4.x.
•  Ijc 15:03, 28 January 2013 (UTC): I've added Xen Version Compatibility and a link from Xen FAW Compatibility. I think this is probably done for now?

Security related docs

George Dunlap: Revamped Driver_Domain and Securing_Xen

cpupools intro / howto

George Dunlap: See Cpupools_Howto

Clear up Xen TODO List

• Setting_boot_order_for_domUs
• XenDevelopmentProjects - although this will need maintaining
• Revamp http://wiki.xen.org/wiki/Xen_PCI_Passthrough. Should be more organized, easier to follow, less verbose, more thorough, and more up-to-date.
• Review and update http://en.wikipedia.org/wiki/Xen - in particular the "Host: Unix-like systems" is out-of-date. The Guest section is too.
• Make Host Install and Guest Install more useful
  •  Lars.kurth: Note: both pages share Template:Distro_Resources
  • Docs for many distros are missing: identify what docs are missing or out of date and put them on the todo list
• Feature Status Doc : Xen_Release_Features
• Xen Overview which explains the top level architectural features and options, trade-offs and links to examples tutorials that show how you set these up
• List i.e. stuff what to test after packaging. This would avoid the current state of affairs where most distros are infact broken w/re to Xen. See Distros
• Installation Guides: How to install on various distros. Tag with Category:Host Install and Category:Guest_Install.
• Tuning
• vcpu pinning (part of Tuning)

Document Policy on Maintenance Releases

Which releases are supported, for how long. Owners. As well as a mechanism for individuals (or vendors) to take ownership of older releases (as is the case for Xen 3.4).

•  Ijc 16:07, 26 November 2012 (UTC): Attempt to document current process: http://lists.xen.org/archives/html/xen-devel/2012-11/msg01389.html
•  Lars.kurth 12:48, 22 January 2013 (UTC): Is this done, see Xen_Maintenance_Releases?
•  Ijc 14:01, 22 January 2013 (UTC): Doc is complete and patches to reference it are in the various trees.

Document {deb,rpm,tar}-pkg targets in kernel

Mainline_Linux_Kernel_Configs talks about the obsolete and Debian specific make-kpkg tool. Should reference the kernels own foo-pkg targets instead.

•  Ijc 12:12, 28 January 2013 (UTC): Done. Made a bunch of other cleanups too.