Comment 0 for bug 1509325

did you saw something like

2015-10-23 10:57:32.314 4666 DEBUG fuel_agent.utils.utils [-] Trying to execute command: chroot /tmp/target /usr/sbin/grub-install /dev/vda
2015-10-23 10:57:33.823 4666 DEBUG fuel_agent.utils.utils [-] Trying to execute command: chroot /tmp/target /usr/sbin/grub-install /dev/vdb
2015-10-23 10:57:34.491 4666 DEBUG fuel_agent.utils.utils [-] Trying to execute command: chroot /tmp/target /usr/sbin/grub-install /dev/vdc
2015-10-23 10:57:35.011 4666 DEBUG fuel_agent.manager [-] Preventing nailgun-agent from doing anything until it is unlocked
2015-10-23 10:57:35.012 4666 DEBUG fuel_agent.utils.utils [-] Trying to execute command: mkdir -p /tmp/target/var/log/upstart
2015-10-23 10:57:35.021 4666 ERROR fuel_agent.cmd.agent [-] can't write str to text stream
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent Traceback (most recent call last):
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent File "/usr/lib/python2.6/site-packages/fuel_agent/cmd/agent.py", line 97, in main
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent getattr(mgr, action)()
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent File "/usr/lib/python2.6/site-packages/fuel_agent/manager.py", line 549, in do_provisioning
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent self.do_bootloader()
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent File "/usr/lib/python2.6/site-packages/fuel_agent/manager.py", line 536, in do_bootloader
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent (mount2uuid[fs.mount], fs.mount, fs.type))
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent File "/usr/lib64/python2.6/io.py", line 1515, in write
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent s.__class__.__name__)
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent TypeError: can't write str to text stream
2015-10-23 10:57:35.021 4666 TRACE fuel_agent.cmd.agent

Source iso : http://jenkins-product.srt.mirantis.net:8080/view/custom_iso/job/custom_8.0_iso/303/
Failed BVT: http://jenkins-product.srt.mirantis.net:8080/view/custom_iso/job/8.0.custom.ubuntu.bvt_2/110/
builded master + https://review.openstack.org/#/c/238574/