Reason for Volume creation failures is not displayed

[Lin Hua Cheng]

When creating a Volume from Volume Snaphot, a Volume Size larger than the snaphot was specified.

Error displays "unable to create volume." , it would be helpful if the exception message is included in the message. This way, the user can adjust the volume sizeto match the snapshot and fix the error.

[chenhaiq (chenhaiq)]

It is because cinder api does not provide error message

[Julie Pichon (jpichon)]

As chenhaiq noted, the cinder creation API call is asynchronous and we don't get an error message back if something goes wrong. There's a blueprint about it on the Cinder side but it's a bit vague and doesn't seem to have generated much interest so far.

https://blueprints.launchpad.net/cinder/+spec/return-error-messages-to-horizon

[Cindy Lu (clu-m)]

Hi Julie,

We can do a front-end check between the volume size and the snapshot size and show an error message. That was what I was thinking.

And there were also a blueprint on the Horizon side for showing more useful error messages - I don't think it's made much progress either.

[sandeep mane (sandeep-mane)]

hi,

I have executed cinder CLI commands to verify this error [using master branch code]
I found, we can create volume with bigger size from volume snapshot, here volume size larger than the snapshot was specified.
it never show any error message on console, its shows available status

can you please provide us more detail on this?

Regards,
Sandeep.

[John Griffith (john-griffith)]

Cinder introduced extend capability a while back, so you can in fact create from source or snapshot a volume that's "larger" than the original. You just can't go the other way.

Extend is easy because you don't have to worry about eating somebody's file system etc. So in the case you describe, we do the create, copy the data and then do an extend.

[sandeep mane (sandeep-mane)]

Hi,

Any updates here

--sandeep

[Gary W. Smith (gary-w-smith)]

This error is not reproducible, which matches John Griffith's explanation that cinder now supports creating a volume whose size is greater than the snapshot. The broader issue of enabling the display of cinder messages should be dealt with in a blueprint.