Failed to attach volume to an instance, sg_scan file not found. This warning and error occur when the sg3-utils package is not installed on the Compute node. The IDs in your message are unique to your system: ERROR nova.compute.manager [req-cf2679fd-dd9e-4909-807f-48fe9bda3642 admin admin|req-cf2679fd-dd9e-4909-807f-48fe9bda3642 admin admin] [instance: 7d7c92e0-49fa-4a8e-87c7-73f22a9585d5|instance: 7d7c92e0-49fa-4a8e-87c7-73f22a9585d5] Failed to attach volume 4cc104c4-ac92-4bd6-9b95-c6686746414a at /dev/vdcTRACE nova.compute.manager [instance: 7d7c92e0-49fa-4a8e-87c7-73f22a9585d5|instance: 7d7c92e0-49fa-4a8e-87c7-73f22a9585d5] Stdout: '/usr/local/bin/nova-rootwrap: Executable not found: /usr/bin/sg_scan

Run this command on the Compute node to install the sg3-utils package: $ sudo apt-get install sg3-utils