Tolerance of pre-existing software-RAID by ydirson · Pull Request #6 · xcp-ng/host-installer

ydirson · 2022-12-09T19:30:27Z

Primary goal of this PR is avoid a pre-existing software RAID configuration to block usage of the disks that were used for that RAID. Those were at best not shown as available, or caused installation errors when selected (on disks with partitions that were part of a RAID), or even successful-looking installations that were not booting (when attempting to install on a RAID whose members were partitions).

The basic idea is to prevent assembling of pre-existing RAID volumes, and add an explicit option to trigger such assembling to allow upgrade/restore operations on systems installed on RAID. It also prevents, while RAIDs were not assembled, adding upgrade/restore choices to the user, of systems installed on RAID.

This filtering-out of restoration choice is extended to any backup partition referring to a non-accessible device, which as a side-effect will make it impossible to start a "restore" operation of a too-old version, which would be doomed to fail because of a dom0 device id change (as seen e.g. in https://xcp-ng.org/forum/topic/6573/upgrade-xenserver-7-to-xcp-ng-8-2-1).

Note this includes PR xenserver#20 to help the user understand which exact choices are really presented.

Note that some points are not currently addressed:

filtering out of disks whose partitions are in a RAID -- but then, this would only be needed when such a RAID is assembled, and we only offer to assemble pre-existing RAID when there are disks with a RAID superblock; so they would only appear when there are both a (supported) disk-level RAID, and an (unsupported) partition-level RAID; at this point the user is very likely already working on the supported RAID, so it is not sure there is really a problem left to address here
prevention of installation of a partition-level RAID -- those would only appear to be available in the same situation

TODO:

The "Back" button on the page displaying your installation options (install, restore, upgrade...) sends back to scanning for existing products and then to the same page again.

startup/01-installer.rules

…for user Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

Adding disk vendor and model would be useful, but can take too much horizontal space, especially for good old 80x25 resolution, so we use a shorter string with just the disk size for disambiguation. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

tui/installer/screens.py

Reasons to have this here include: * don't require changes to srpm when the set of installed files change * make installer development faster by deploying directly to a filesystem This installation process still depends by default on the sm package being installed, but through SM_ROOT variable it can now be run on a dev machine where this is not the case, it just needs an unpacked version of the package. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

mdadm output is like "MD_DEVNAME=127 which results in getHumanDiskName giving a name of "RAID: 127(sda,sdb)". This fixes the problem and gets us "RAID: md127(sda,sdb)" instead. Also slightly improve readability with tuple unpacking. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

This prevents 65-md-incremental.rules from assembling every RAID it identifies, we want to have control over that, so we can reuse a former RAID member for other purposes. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

This causes the "Back" button in primary-disk selection to trigger a rescan for products. This provides support for allowing the user to enable layers of block-device composition (e.g. "md" software RAID, not part of this PR) and then scan those RAID volumes for products. This could even be used for arbitrary manual block-device setup from shell on alternate console. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

It has value for a user expecting an existing product to get notified that none was found. Moreover, this will allow a user to get to the "assemble RAID" choice even when no product was detected. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

… RAID This adds an option to enable *all* RAID devices found. This is less flexible than a more selective mechanism would be, but really simple and covering all known use-cases. It filters out from choices presented to the user both "update of" and "restore to" entries refering to a disk that is part of a md RAID (though in practice only the "update" case is likely to appear). This avoids the case where a user gets those entries before explicitly assembling RAIDs, and thus avoids breaking a RAID by mistake. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

…er to assemble RAID This commit is kept as separate until decided this is the way to go, but would be better squashed. Introduce installer feature flags, and hide the RAID-assembling feature behind the `raid-assemble` flag.

…ound This will avoid issues where users attempt to upgrade from a very old version, and a dom0 kernel driver evolution changed the /dev/disk/by-id/ identifier for the disk, and when the backup became invalid after a hardware change. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

ydirson · 2023-05-22T14:07:20Z

Repushed with the same contents as upstream PR, instead of maintaining 2 branches.
Besides, old branch was using a defunct target branch.

Wescoeur · 2023-05-25T08:33:17Z

answerfile.py

+        results = {}
+        nodes = getElementsByTagName(self.top_node, ['assemble-raid'])
+        if nodes:
+            results['assemble-raid'] = True # possibly useless


Why useless? :)

Wescoeur · 2023-05-25T08:35:13Z

answerfile.py

+        if nodes:
+            results['assemble-raid'] = True # possibly useless
+            logger.log("Assembling any RAID volumes")
+            rv = util.runCmd2([ 'mdadm', '--assemble', "--scan" ])


Mix of simple and double quotes?

Also do you have a warn with pycodestyle? It seems to me that spaces next to the brackets can trigger a message.

rzr · 2025-12-17T14:46:46Z

This PR has been identified as "not ready": it can't be merged because of conflicts.
Please mark it as "draft, until work is resumed or taken over.
It will help reviewers to prioritize the mergeable PRs, Thank you.

ydirson force-pushed the yann/software-raid branch 2 times, most recently from af0eee9 to 5f445db Compare December 12, 2022 12:44

ydirson requested review from Wescoeur, benjamreis and stormi December 12, 2022 12:50

benjamreis approved these changes Dec 12, 2022

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ydirson force-pushed the yann/software-raid branch 3 times, most recently from 80ad661 to 38721e3 Compare December 13, 2022 09:33

This was referenced Dec 13, 2022

Software RAID install on previous used mdadm disks xcp-ng/xcp#107

Open

tui: show the disk on which an existing installation or backup is found xenserver/host-installer#20

Merged

stormi reviewed Dec 13, 2022

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startup/01-installer.rules Outdated Show resolved Hide resolved

ydirson force-pushed the yann/software-raid branch 2 times, most recently from 946713e to 28401b7 Compare December 14, 2022 17:17

ydirson added 2 commits December 15, 2022 12:30

New diskutil.getHumanDiskLabel to centralize formatting of disk name …

fc45c60

…for user Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

ydirson commented Dec 15, 2022

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tui/installer/screens.py Outdated Show resolved Hide resolved

ydirson force-pushed the yann/software-raid branch from 28401b7 to 5d7e353 Compare December 15, 2022 16:49

ydirson force-pushed the yann/software-raid branch 2 times, most recently from 6474110 to 2f25984 Compare January 24, 2023 18:04

ydirson added 9 commits January 25, 2023 10:58

udev: force ANACONDA flag to prevent RAID assembling

03b3bb1

This prevents 65-md-incremental.rules from assembling every RAID it identifies, we want to have control over that, so we can reuse a former RAID member for other purposes. Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

answerfile: add support for assembling pre-existing RAID

406503f

Signed-off-by: Yann Dirson <yann.dirson@vates.fr>

ydirson force-pushed the yann/software-raid branch from 2f25984 to 406503f Compare May 22, 2023 14:06

ydirson changed the base branch from 10.10.x-8.3 to 10.10.5-8.3 May 22, 2023 14:07

Wescoeur reviewed May 25, 2023

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ydirson changed the base branch from 10.10.5-8.3 to 10.10.11-8.3 December 15, 2023 14:23

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Tolerance of pre-existing software-RAID#6

Tolerance of pre-existing software-RAID#6
ydirson wants to merge 11 commits into10.10.11-8.3from
yann/software-raid

ydirson commented Dec 9, 2022 •

edited by stormi

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ydirson commented May 22, 2023 •

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ydirson commented Dec 9, 2022 •

edited by stormi

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ydirson commented May 22, 2023 •

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