Avoid grey-market downloads. Instead, invest in a CML Personal license—it not only gives you the xrv9k-fullk9 image but also includes an orchestration layer to connect multiple nodes.
This will recursively set the correct ownership and permissions for all files in the /opt/unetlab/addons/ directory. Xrv9k-fullk9-7.2.2 Download
The licensing model for the XRv 9000 has evolved, and version 7.2.2 supports the Cisco Smart Licensing model. Avoid grey-market downloads