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Hi,
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<div>In a prototype, we have improved Nova's scheduling error messages. </div>
<div>This helps both developers and end users better understand the </div>
<div>scheduler problems that occur on creation of an instance.</div>
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<div>When a scheduler error happens during instance creation via the nova </div>
<div>upstream, we get the following message on the Overview tab </div>
<div>(Horizon dashboard): "No valid host was found." This doesn't give us </div>
<div>enough information about what really happened, so our solution was to </div>
<div>add more details on the instance's overview page, e.g.:</div>
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<div>**Fault:Message** attribute provides a summary of why each host can not </div>
<div>satisfy the instance’s resource requirements, e.g. for controller-0, it </div>
<div>indicates “No valid host was found. Not enough host cell CPUs to fit </div>
<div>instance cell” (where cell is a numa-node or socket).</div>
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<div>**Fault:Details** attribute provides even more detail for each </div>
<div>individual host, for example it shows that the instance “required” 2 </div>
<div>CPU cores and shows the “actual” CPU cores available on each “numa” </div>
<div>node: “actual:0, numa:1” and “actual:1, numa:0”.</div>
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<div>These details are also present using the OpenStack CLI, in the </div>
<div>_fault_ attribute:</div>
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<div>- openstack server show <instance> </div>
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<div>With that in mind, we'd like to know if you are open to consider such </div>
<div>a change. We are willing to submit a spec and upstream that </div>
<div>implementation.</div>
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<div>Regards,</div>
- nicodemos<br>
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