[live-migration] harden resume against stdio and exit wait loss - #2866
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Harsh Rawat (rawahars) wants to merge 3 commits into
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[live-migration] harden resume against stdio and exit wait loss#2866Harsh Rawat (rawahars) wants to merge 3 commits into
Harsh Rawat (rawahars) wants to merge 3 commits into
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When a live migration rolls back to the source, the VM resumes but the container's stdout/stderr were dropped during blackout and never restored, so anything watching the container's output saw it stop for good. Resume now brings those streams back the same way the destination already does, so a rolled-back container keeps streaming its output as if the migration had never been attempted. Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
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A process reopened on the destination relies on the exit wait its previous owner left outstanding in the guest. If the process exited while no bridge was connected, the guest's response to that wait was dropped and never re-sent, so the reopened process would wait for an exit that is never reported. On reopen, probe with a short bounded wait: an already-exited process returns its retained exit code immediately, while a still-running one lets the probe time out and the outstanding wait is watched as before. Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
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Manish Ranjan Mahanta (marma-dev) and
Shreyansh Sancheti (shreyanshjain7174)
August 9, 2026 20:12
| if existing, dup := brdg.rpcs[id]; dup { | ||
| // A source rollback re-opens a process whose wait is still outstanding; | ||
| // hand back that call. | ||
| return existing, nil |
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PreregisterRPC returns the existing call for a duplicate ID, but OpenProcessWithIO keeps the new Process.waitResp. The existing call still unmarshals into the old response object. I reproduced this on the combined #2867 + #2866 branch: completing the reused wait with exit code 42 made the new Process.ExitCode() return 0. Can we preserve the response object together with the reused call, and add that case to the test?
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Thanks for the feedback. Addressed the same in db73516
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
Shreyansh Sancheti (shreyanshjain7174)
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Aug 10, 2026
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LGTM!
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Summary
Two blackout-related gaps in live migration, each restoring behavior the connection drop had broken:
Testing
Ran
live-migrationsource rollback with a single container and with 10 containers; validated logs stream back on the source.