Live migration fails with qemu-img >= 2.10: "Failed to get shared "write" lock\nIs another process using the image?" Looks like this is pretty new: http://logs.openstack.org/01/503601/7/check/gate-tempest-dsvm-multinode-live-migration-ubuntu-xenial/b19b77c/logs/screen-n-api.txt.gz?level=TRACE#_Sep_19_17_47_11_508623 Sep 19 17:47:11.508623 ubuntu-xenial-2-node-rax-ord-10997038