故障现象
网络验证失败，报错信息如下：
Repo availability verification using public network failed on following nodes Untitled (99:1b).
Following repos are not available - http://archive.ubuntu.com/ubuntu/, http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/.
Check your public network settings and availability of the repositories from public network. Please examine nailgun and astute logs for additional details.
解决办法：
Fuel在安装Openstack的时候需要下载ubuntu源，因此在网络验证是会检查Fuel master节点以及各虚拟机是否可以连通ubuntu源，检查默认的配置如下所示：
从图中可以看出，有的配置为本地源（在Fuel Master节点），有的配置为官网的源，由于之前已在Fuel master节点上传了ubuntu的源，mos源默认自带，因此，修改上述各地址，依次如下所示：
deb http://10.20.0.2:8080/mirrors/ubuntu/ trusty main universe multiverse
deb http://10.20.0.2:8080/mirrors/ubuntu/ trusty-updates main universe multiverse
deb http://10.20.0.2:8080/mirrors/ubuntu/ trusty-security main universe multiverse
deb http://10.20.0.2:8080/mitaka-9.0/ubuntu/x86_64 mos9.0 main restricted
deb http://10.20.0.2:8080/mirrors/mos-repos/ubuntu/9.0/ mos9.0-updates main restricted
deb http://10.20.0.2:8080/mirrors/mos-repos/ubuntu/9.0/ mos9.0-security main restricted
deb http://10.20.0.2:8080/mirrors/mos-repos/ubuntu/9.0/ mos9.0-holdback main restricted
deb http://10.20.0.2:8080/mitaka-9.0/ubuntu/auxiliary auxiliary main restricted
PS：上述地址在IP:8080后的地址都是在Fuel Master节点/var/www/nailgun目录下的相对地址，可以检查是否存在对应目录。
[root@fuel nailgun]# ls
bootstraps centos dump error.html extra-repos index.html mirrors mitaka-9.0 mos-centos targetimages ubuntu
保存修改后，重新验收，验证通过。