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Matt,

Thank you so much for the clarification! I'm glad it's not a bug, and
now it will be easier to understand the difference between the
behaviours and adjust accordingly.


Best regards,

Mary

On 23/07/2019 00:21, Matt Riedemann wrote:
> On 7/14/2019 7:35 AM, Mary Atakova wrote:
>> I try to live-migrate a VM, and I do it through nova cli and through
>> Horizon, and nova-api logs contain different data depending on the
>> way I do it.
>>
>> 1. nova cli
>>
>> I run the command:
>>
>> nova live-migration 17359460-d23c-4acc-a9b1-5cf117b54430
>>
>> and it shows up in nova-api logs as:
>>
>> {"os-migrateLive": {"block_migration": "auto", "host": null}}
>>
>> 2. horizon
>>
>> I run live migration via Horizon with unchecked Disk Overcommit and
>> unchecked Block Migration.
>>
>> It shows up in nova-api logs as:
>>
>> {"os-migrateLive": {"disk_over_commit": false, "block_migration":
>> false, "host": null}}
>>
>> This difference can lead to different parameters provided for live
>> migration when block_migration: auto is translated into
>> block_migration: true.
>
> The difference is in the compute API microversion used. The nova CLI
> by default negotiates the highest microversion to use between what the
> client understands and what the server provides. The 'auto' value for
> the block_migration parameter was added in 2.25 and disk_over_commit
> was removed in 2.25. Horizon is likely not specifying a specific
> microversion so it defaults to 2.1 and that's why you're getting
> "disk_over_commit": false, "block_migration": false because you
> unchecked those check boxes.
>
> In other words, for Horizon to support compute API 2.25 there would be
> an "Auto" option for the Block Migration value.
>