cinder read-only volume is either writable or cannot attach

Solution Verified - Updated -


  • Kilo with EMC xtremio array as backend storage.
  • Created volume from xtremio backend, make it readonly 'cinder readonly-moe-update true'
  • There were a few times the volume is attached to instance with no issue, but it is still writable
  • And on the same system, when we repeated some times with the same test, readonly volume is not able to attach to instance anymore with error:
  'Exception during message handling: Invalid input received: Invalid attaching mode 'rw' for volume'


  • Red Hat Open Stack

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