Bug 1443066

Summary: Unable to encode message payload when creating a guest with 16384 virtio-scsi disks
Product: [Community] Virtualization Tools Reporter: Richard W.M. Jones <rjones>
Component: libvirtAssignee: Libvirt Maintainers <libvirt-maint>
Status: CLOSED DEFERRED QA Contact:
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Priority: medium    
Version: unspecifiedCC: berrange, heinzm, libvirt-maint
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Last Closed: 2024-12-17 12:35:56 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 910269    
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log from libvirt client
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log from libvirtd none

Description Richard W.M. Jones 2017-04-18 12:10:05 UTC 
Description of problem:

When creating a guest with 16384 virtio-scsi disks, libvirt
fails with:

  Unable to encode message payload

Version-Release number of selected component (if applicable):

libvirt-daemon-3.2.0-1.fc27.x86_64

How reproducible:

100%

Steps to Reproduce:
1. Create a guest with 16384 virtio-scsi disks.  See the attached
   file for libvirt XML and so on.
Comment 1 Richard W.M. Jones 2017-04-18 12:12:32 UTC 
Created attachment 1272310 [details]
log from libvirt client
Comment 2 Richard W.M. Jones 2017-04-18 12:13:36 UTC 
Created attachment 1272312 [details]
log from libvirtd
Comment 3 Heinz Mauelshagen 2022-07-28 11:43:45 UTC 
As this bz is about payload size restriction in general, it applies to any retrieval!

This for instance prohibits defining a static vm configuration with such large config e.g. for block devices
(i.e . "virsh dumpxml $domain > $domain.xml;virsh config $domain.xml"), hence requiring to reattach them after
the vm got destroyed which can take hours and thus delay related tests.

Please mind that the maximum command line length of typically 2 MiB characters is also a limiting factor preventing qemu to start with scaled up VM configurations.

Changed prority+severity to get this fixed.
Comment 4 Heinz Mauelshagen 2022-07-29 22:08:34 UTC 
Also, an unrelated virt-clone fails with the same error:

# virt-clone -o fedora-36 -n fedora-36-hm --preserve-data -f /dev/rhel/fedora-36-hm 
ERROR    Unable to encode message payload
Comment 5 Daniel Berrangé 2024-12-17 12:35:56 UTC 
Thank you for reporting this issue to the libvirt project. Unfortunately we have been unable to resolve this issue due to insufficient maintainer capacity and it will now be closed. This is not a reflection on the possible validity of the issue, merely the lack of resources to investigate and address it, for which we apologise. If you none the less feel the issue is still important, you may choose to report it again at the new project issue tracker https://gitlab.com/libvirt/libvirt/-/issues The project also welcomes contribution from anyone who believes they can provide a solution.