Comment 22 for bug 293586

Yes, exactly what Steve said. I certainly did not mean to imply that you must use a public mirror; it's entirely possible and reasonable to use a private mirror for installations - it just needs to be a little more than a mounted DVD image. For example, something like the following debmirror invocation is sufficient (based on what I use myself):

  debmirror /mirror/ubuntu --host gb.archive.ubuntu.com --method http \
          --root /ubuntu/ --dist=intrepid,intrepid-security,intrepid-updates,intrepid-proposed \
          --section main,main/debian-installer,restricted,restricted/debian-installer \
          --arch=amd64,i386 --ignore=main/installer-

If you're reloading machines several times a month, it will be in your interest to have them picking up updates from a single local mirror rather than over the Internet anyway! (I'm assuming that you want to test against 8.10 plus updates as well as, or perhaps instead of, merely 8.10. Most software vendors do, since 8.10 plus updates is what real users use.)