From Fedora Project Wiki
 
(27 intermediate revisions by 3 users not shown)
Line 2: Line 2:
  
 
== Summary ==
 
== Summary ==
Only create "host-only" initramfs images. A generic fallback image should be installed by anaconda on installation/update and never ever be removed.
+
Only create "host-only" initramfs images. A generic fallback image will be generated, if it does not exist and never ever be removed.
  
 
== Owner ==
 
== Owner ==
Line 10: Line 10:
 
== Current status ==
 
== Current status ==
 
* Targeted release: [[Releases/19 | Fedora 19 ]]  
 
* Targeted release: [[Releases/19 | Fedora 19 ]]  
* Last updated: 2013-01-29
+
* Last updated: 2013-05-16
* Percentage of completion: 20%
+
* Percentage of completion: 100%
  
 
== Detailed Description ==
 
== Detailed Description ==
Line 26: Line 26:
 
== Scope ==
 
== Scope ==
 
<!-- What work do the developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
 
<!-- What work do the developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
* dracut is already capable of producing host-only initramfs images, as well as rescue images
+
* [ DONE ] dracut is already capable of producing host-only initramfs images, as well as rescue images
* dracut has to implement "dracut --regenerate-all" to regenerate all normal initramfs with the current hardware
+
* [ DONE ] dracut has to source config files from "/usr/lib/dracut/dracut.conf.d", although the same filenames in "/etc/dracut/dracut.conf.d" will have priority
* dracut has to ship "/usr/lib/dracut/dracut.conf.d/01-hostonly.conf"
+
* [ DONE ] dracut has to be changed to create the rescue initramfs image and the rescue boot entry, if it does not yet exist
* dracut has to source config files from "/usr/lib/dracut/dracut.conf.d", although the same filenames in "/etc/dracut/dracut.conf.d" will have priority
+
* [ DONE ] dracut has to provide the following subpackages: dracut-nohostonly and dracut-norescue
* dracut has to be changed to create the rescue initramfs image and the rescue boot entry, if it does not yet exist and call "yumdb set installonly keep kernel-<version>" for the kernel, which is used for the rescue image, otherwise kernel modules cannot be loaded in the real root.
+
* [ DONE ] dracut has to implement "dracut --regenerate-all" to regenerate all normal initramfs with the current hardware
 +
 
 +
* [ REJECTED ] <strike>and call "yumdb set installonly keep kernel-$version" for the kernel, which is used for the rescue image, otherwise kernel modules cannot be loaded in the real root.</strike> Reason: the rescue image has enough kernel modules already to mount the root device and /usr, so that the user can call "dracut --regenerate-all".
 +
 
 +
* [ REJECTED ] <strike>dracut has to ship "/usr/lib/dracut/dracut.conf.d/99-hostonly.conf" with: <nowiki>[[ $hostonly ]]</nowiki> || hostonly="yes" in a "dracut-hostonly" subpackage.</strike> Reason: we ship dracut-norescue and dracut-nohostonly packages. The default setting should need no additional subpackage.
 +
 
 +
* [ FIXED ] fix lorax/livecd-tools to use --no-hostonly when creating the initramfs for the LiveCD https://bugzilla.redhat.com/show_bug.cgi?id=921422
  
 
== How To Test ==
 
== How To Test ==
Line 60: Line 66:
 
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this feature depends?  In other words, completion of another feature owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel feature)? -->
 
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this feature depends?  In other words, completion of another feature owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel feature)? -->
 
* dracut
 
* dracut
 +
* grubby-8.23-1.fc19
  
 
== Contingency Plan ==
 
== Contingency Plan ==
Line 72: Line 79:
 
<!-- The Fedora Release Notes inform end-users about what is new in the release.  Examples of past release notes are here: http://docs.fedoraproject.org/release-notes/ -->
 
<!-- The Fedora Release Notes inform end-users about what is new in the release.  Examples of past release notes are here: http://docs.fedoraproject.org/release-notes/ -->
 
<!-- The release notes also help users know how to deal with platform changes such as ABIs/APIs, configuration or data file formats, or upgrade concerns.  If there are any such changes involved in this feature, indicate them here.  You can also link to upstream documentation if it satisfies this need.  This information forms the basis of the release notes edited by the documentation team and shipped with the release. -->
 
<!-- The release notes also help users know how to deal with platform changes such as ABIs/APIs, configuration or data file formats, or upgrade concerns.  If there are any such changes involved in this feature, indicate them here.  You can also link to upstream documentation if it satisfies this need.  This information forms the basis of the release notes edited by the documentation team and shipped with the release. -->
* This Fedora release ships with an initramfs tailored especially for your computer hardware. If you change your machine or significant hardware, you might have to boot with the "Rescue System" boot entry and execute "dracut --regenerate-all". If you want your initramfs to be hardware independent, execute "ln -s /dev/null /etc/dracut.conf.d/01-hostonly.conf".
+
* This Fedora release builds an initramfs tailored especially for your computer hardware. If you change your machine or partitions or significant hardware, you might have to boot with the "Rescue" boot entry and execute "dracut --regenerate-all". If you want your initramfs to be hardware independent, install the "dracut-nohostonly" rpm package. If you don't want rescue images at all (like in virtual machines), install the "dracut-norescue" rpm package.
  
 
== Comments and Discussion ==
 
== Comments and Discussion ==
 
* See [[Talk:Features/DracutHostOnly]]  <!-- This adds a link to the "discussion" tab associated with your page.  This provides the ability to have ongoing comments or conversation without bogging down the main feature page -->
 
* See [[Talk:Features/DracutHostOnly]]  <!-- This adds a link to the "discussion" tab associated with your page.  This provides the ability to have ongoing comments or conversation without bogging down the main feature page -->
  
[[Category:FeatureReadyForFesco]]
+
[[Category:FeatureAcceptedF19]]
 
<!-- When your feature page is completed and ready for review -->
 
<!-- When your feature page is completed and ready for review -->
 
<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
 
<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
 
<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
 
<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
 
<!-- A pretty picture of the page category usage is at: https://fedoraproject.org/wiki/Features/Policy/Process -->
 
<!-- A pretty picture of the page category usage is at: https://fedoraproject.org/wiki/Features/Policy/Process -->

Latest revision as of 14:57, 28 June 2013

Dracut HostOnly

Summary

Only create "host-only" initramfs images. A generic fallback image will be generated, if it does not exist and never ever be removed.

Owner

Current status

  • Targeted release: Fedora 19
  • Last updated: 2013-05-16
  • Percentage of completion: 100%

Detailed Description

Current initramfs images contain most of the kernel drivers to boot from any hardware. This results in a very big initramfs, which takes a long time to load on system start and a long time to create on kernel updates. Switching to host-only will improve the situation. To cope with hardware change, a boot entry "Rescue System" should be installed with a full fledged initramfs also containing debug tools. This boot entry can then be used to recover from hardware changes and also from unforseen software failure after updates.

Benefit to Fedora

Less /boot usage. Faster boot and updates. Full fledged rescue mode available.

Scope

  • [ DONE ] dracut is already capable of producing host-only initramfs images, as well as rescue images
  • [ DONE ] dracut has to source config files from "/usr/lib/dracut/dracut.conf.d", although the same filenames in "/etc/dracut/dracut.conf.d" will have priority
  • [ DONE ] dracut has to be changed to create the rescue initramfs image and the rescue boot entry, if it does not yet exist
  • [ DONE ] dracut has to provide the following subpackages: dracut-nohostonly and dracut-norescue
  • [ DONE ] dracut has to implement "dracut --regenerate-all" to regenerate all normal initramfs with the current hardware
  • [ REJECTED ] and call "yumdb set installonly keep kernel-$version" for the kernel, which is used for the rescue image, otherwise kernel modules cannot be loaded in the real root. Reason: the rescue image has enough kernel modules already to mount the root device and /usr, so that the user can call "dracut --regenerate-all".
  • [ REJECTED ] dracut has to ship "/usr/lib/dracut/dracut.conf.d/99-hostonly.conf" with: [[ $hostonly ]] || hostonly="yes" in a "dracut-hostonly" subpackage. Reason: we ship dracut-norescue and dracut-nohostonly packages. The default setting should need no additional subpackage.

How To Test

  • install F19
  • see two boot entries in grub: first one with the current kernel, second one with the rescue entry
  • /boot should contain one big initramfs belonging to the rescue image. The rest of the initramfs images should be way smaller in comparison.
  • every boot entry must be bootable
  • kernel upgrade must not remove the kernel used for the rescue boot entry

User Experience

User should see no difference, besides faster boot and updates. On boot failure, the user now has a "Rescue system" boot entry.

Dependencies

  • dracut
  • grubby-8.23-1.fc19

Contingency Plan

If the feature cannot be completed, we switch back to non-hostonly initramfs images, which is a configure switch in dracut and very easy to do.

Documentation

Release Notes

  • This Fedora release builds an initramfs tailored especially for your computer hardware. If you change your machine or partitions or significant hardware, you might have to boot with the "Rescue" boot entry and execute "dracut --regenerate-all". If you want your initramfs to be hardware independent, install the "dracut-nohostonly" rpm package. If you don't want rescue images at all (like in virtual machines), install the "dracut-norescue" rpm package.

Comments and Discussion