~/talk

The Magic of the Libvirt Driver – What to Do When You Invariably Hit "No Valid Host"

on YouTube 31m
Talkat OpenInfra Summit 2020 · 2020-10-19..10-23· [software-architecture]

speaker

name:Stephen Finucane
links:none on file

resources

video:https://youtu.be/_4gEYvFSWtk
slides:none on file

summary

Libvirt (QEMU/KVM) is feature‑rich but causes the infamous scheduler “no valid host” when placement, filters and the driver disagree—examples: pinned CPUs used to be silently shared during live migration until Train introduced pcpus to keep pinned and unpinned pools separate; memory with huge pages disables swap and overcommit and often fails late in scheduling; PCI passthrough is racy and drops devices under concurrent boots. Use Train/Rocky or newer, prefer homogeneous hosts or host aggregates, test small and expect to add logging and patches.

AI-written summary · about

chapters (11)

  1. 0:00Introduction
  2. 0:23Overview
  3. 1:32Openstack Nova
  4. 6:03The Libvirt Driver
  5. 9:33Wires
  6. 10:51Placement
  7. 12:39CPU Policies
  8. 17:28Memory Policies
  9. 23:52Filters
  10. 27:00PCI Passthrough
  11. 29:14Conclusion

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