He means simply removing "trusty + armhf" for the "ros" and/or "gazebo" images, I believe (not for the "ubuntu" image).
The harm this causes is that "apt-get update" fails, which causes the whole "docker build" to fail. Here's an example from ppc64el: W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/main/binary-ppc64el/Packages 404 Not Found [IP: 91.189.88.152 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/restricted/binary-ppc64el/Packages 404 Not Found [IP: 91.189.88.152 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/universe/binary-ppc64el/Packages 404 Not Found [IP: 91.189.88.152 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/multiverse/binary-ppc64el/Packages 404 Not Found [IP: 91.189.88.152 80] E: Some index files failed to download. They have been ignored, or old ones used instead. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1711735 Title: source.list for armhf includes trusty-security which does not exist for arm To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-images/+bug/1711735/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs