[DISCUSSION] Hotpatching for Windows Server 2025 (and Windows 11 24H2 - no subscriptions needed!)

Discussion in 'Windows Server' started by kibkalo, Sep 21, 2024.

  1. kibkalo

    kibkalo MDL Expert

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    #1 kibkalo, Sep 21, 2024
    Last edited: Sep 28, 2024
  2. 100

    100 MDL Expert

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  3. kibkalo

    kibkalo MDL Expert

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    In my case, I do see 26100.1656 offered - and it does install without reboot.
    But same moment, KB503894 (2024-07 .net update) is offered - and it does require reboot.
    What is a way to prevent installation of non-Hotpatch updates?
     
  4. 100

    100 MDL Expert

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    As is described in the documentation I linked:
     
  5. kibkalo

    kibkalo MDL Expert

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    #5 kibkalo, Sep 22, 2024
    Last edited: Sep 22, 2024
    (OP)
    The answer was - .NET 2024-07 is a prerequisite, same as LCU 1150.
    If it is installed, next .NET updates are not offered on hotpatch channel

    What about Client 24H2?
    What if we repeat same steps on 26100 Windows 11?
    I would recommend to add to
    Code:
    [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Update\TargetingInfo\DynamicInstalled\Hotpatch.amd64]
    "Source"="Hotpatch Product"
    "Version"="10.0.26100.1"
     
  6. 100

    100 MDL Expert

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    Hm, not sure about that. I'd think that regular .NET updates will be available through WU, and hotpatching documentation mentions that installing these can require a reboot: aka.ms/hotpatchdocs
     
  7. kibkalo

    kibkalo MDL Expert

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    True. Starting with 2024-08 .NET updates don't appear if hotpatch channel is selected. So 2024-07 might be manually added, or it would install and reboot.
    Starting 2024-08 it won't autoinstall
     
  8. 100

    100 MDL Expert

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    No, this way only applies to 2025, because it includes hotpatching in regular editions.

    On 2022 hotpatching is only available in "Azure edition" and has the additional prerequisite of running in Azure or Azure Stack HCI: learn.microsoft.com/en-us/windows-server/get-started/enable-hotpatch-azure-edition
     
  9. kibkalo

    kibkalo MDL Expert

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    #15 kibkalo, Sep 22, 2024
    Last edited: Sep 23, 2024
    (OP)
    My point was that if you don't install KB5039894 before making system hot-patchable, it would install and reboot.
    All later .NET updates (usually requiring reboots) won't display if hotpatch is enabled.

    Update
    Found that 26100.1150 is not a prerequisite, 26100.268 is. Installing it and enabling VBS and hotpatching does the trick
    Hotpatch LCUs KB5037970 (26100.500) and KB5039329 (26100.793) - both include "quarterly base" KB5036908 (26100.268). If I have 26100.268+, enable VBS and AllowRebootlessUpdates, hotpatch channel is only on Windows update.
    And .1150 was "quarterly update", similar to .268. You could install .500 and .793 with no reboots, but .1386 includes .1150 inside, which is not "hot", and if wasn't installed previously requires a reboot.
    I expect new hotpatch LCU in late september and late october. And a new quartely base early november. Late november hotpatch would include it and would require a reboot. Two next updates won't. Nice strategy!
     
  10. kibkalo

    kibkalo MDL Expert

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    I am looking for Microsoft-Windows-Hotpatch-Targeting-Package-amd64-10.0.26100.1
    Can anyone help me?
     
  11. Ace2

    Ace2 MDL Expert

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    could you extract it from Server 2025 Datacenter 26100.1 with SxSv1 ?
     
  12. kibkalo

    kibkalo MDL Expert

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    It is not a part of it :(
    Microsoft-Windows-Hotpatch-Payload-Package and Microsoft-Windows-Hotpatch-Utility-Package are, but not Microsoft-Windows-Hotpatch-Targeting-Package or Microsoft-Windows-Hotpatch-Targeting-Gated-Package
     
  13. Ace2

    Ace2 MDL Expert

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  14. kibkalo

    kibkalo MDL Expert

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    Well, we haven't moved much there.
    I have done export of Payload and Utility packages before that.
    And I didn't find a way to reconstruct Hotpatch Targeting package.
    Have made client use server targeting - get updates from server channel, but yet not from the hotpatch channel, need one more step.