Comment 8 for bug 1569859

The issue has been reproduced the following way:
1. Install Fuel 9.0-244
2. add fuel-agent into ubuntu repo on fuel and rebuild bootstrap image due https://bugs.launchpad.net/fuel/+bug/1543233
3. Patch nailgun https://review.openstack.org/gitweb?p=openstack/fuel-web.git;a=patch;h=d2ec3c1e49e87958b71eca9f65dc1674f444f907 due https://bugs.launchpad.net/fuel/+bug/1570509
4. apply changes https://review.openstack.org/gitweb?p=openstack/fuel-web.git;a=patch;h=67d97c00632601a2d5d4dc8100906cc1543bd3f4
(manager.py is attached. there was manual changing of the file)
5. install uwsgi uwsgi-plugin-python python-uwsgidecorator:
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -Uvh epel-release-7*.rpm
sed -i s/^enabled=1/enabled=0/g /etc/yum.repos.d/epel.repo
yum --enablerepo=epel install uwsgi uwsgi-plugin-python python-uwsgidecorator
6. restart nailgun and receiverd

After configuring and clicking "deploy changes" nailgun was unreachable during ~10 minutes

log folder from fuel http://mos-scale-share.mirantis.com/fuel_logs_1569859_25-04-2016.tar.gz