Hi team I am following the image build instructions from : https://docs.starlingx.io/developer_guide/ If these are not the correct instructions please let me know. I am stuck at the point of: $ docker build --tag $USER:centos-mirror-repository --file Dockerfile . I am behind a proxy and i already set up docker for proxy ( i tested docker run hello-world and works fine ) and set up the Dockerfile as suggested: ENV http_proxy " http://your.actual_http_proxy.com:your_port " ENV https_proxy " https://your.actual_https_proxy.com:your_port " ENV ftp_proxy " http://your.actual_ftp_proxy.com:your_port " RUN echo " proxy=http://your-proxy.com:port " >> /etc/yum.conf However, I am still facing this error Cannot find a valid baseurl for repo: base/7/x86_64 Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container error was 12: Timeout on http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container: (28, 'Resolving timed out after 30541 milliseconds') The command '/bin/sh -c yum install -y epel-release sudo vim-enhanced net-tools git /usr/bin/yumdownloader rpm-build rpm-sign deltarpm wget bind bind-utils && rm /etc/yum.repos.d/CentOS-Sources.repo /etc/yum.repos.d/epel.repo' returned a non-zero code: 1 Full log at : https://hastebin.com/omuzimenid.sql Any help is more than welcome Regards Victor Rodriguez