[PVE-User] Live VM migration 6.3 to 6.2 fails

[Daniel Berteaud]

----- Le 2 Déc 20, à 9:11, Christian Balzer chibi at gol.com a écrit :

> Hello,
> 
> yes I know that migrating back to an older version is not guaranteed but
> I'm rather confused as to why this happens.
> 
> Firstly this, more details below:
> ---
> 2020-12-02 16:34:08 start migrate command to tcp:10.0.0.11:60000
> 2020-12-02 16:34:09 migration status error: failed
> 2020-12-02 16:34:09 ERROR: online migrate failure - aborting
> 2020-12-02 16:34:09 aborting phase 2 - cleanup resources
> 2020-12-02 16:34:09 migrate_cancel
> 2020-12-02 16:34:11 ERROR: migration finished with problems (duration 00:00:08)
> TASK ERROR: migration problems
> ---
> 
> That's all I get, where would one find the exact issue?
> 
> Now for the details, in the previous minor upgrade we saw a similar issue,
> but that only affected VMs which had been created on an upgraded node, old
> ones were fine to move in both ways.
> OK, that was because of new features int he VM definition not present on
> the old version, understandable.
> 
> With this one on a (more frequently updated) test cluster 6.3 to 6.2
> migrations also works, the test cluster old nodes are at
> pve-manager (6.2-12), the one with issues are pve-manager (6.2-6).
> I however see nothing in the changelogs which would explain this difference.
> 
> In general being able to live migrate back to a node with the previous
> version is a very desirable situation, since if there are issues/bugs (on
> the VM level) with the new version there no longer is an impact free way
> of reverting if this functionality is not present.
> 


That's most likely the QEMU version 5.1 on the 6.3 node vs QEMU 5.0 on the 6.2 one.
There's no migration support from newer to older, only from older to newer.

Cheers,
Daniel

-- 
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Daniel Berteaud 
FIREWALL-SERVICES SAS, La sécurité des réseaux 
Société de Services en Logiciels Libres 
Tél : +33.5 56 64 15 32 
Matrix: @dani:fws.fr 
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