Google Compute Engine gives error while instantiating with existing boot and data disk
I originally created an instance with a persistent boot and disk drive. I wanted to test that if something happened to the instance, I could just recreate one with the same boot and disk drive and it would work as usual.
However, I get this error when instantiating from the developer console:
Invalid value for field 'resource.disks[1].source': 'site-data'. Must be a URL to a valid Compute resource of the correct type.
The only thing I do differently is set the boot drive to the previous boot drive, not the new image, and map the site data drive on read / write.
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I suggest you try again - it looks like their developer web console was broken within a few days, copying the time you asked your question. It seems to be working correctly.
I also got this error when trying to create an instance that included an additional Persistent Disk. Instantiating with only the boot drive worked fine, but trying to instantiate with any additional drive (including a new, empty drive) resulted in the same error you reported above.
I used "Need Help?" link in the lower left corner of the Create New Instance web form to report the issue yesterday (10/21/14). While I did not receive any response (I did not pay for any support options), the issue was resolved within 24 hours. Now I can successfully create instances with additional persistent disks.
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