How can schroot works with aufs

I'm using schroot with aufs. Currently, my conf file under \etc\schroot\chroot.d looks like [trusty_chrome] description=Ubuntu 14.04 Trusty running Chrome and Adobe Flash directory=/srv/chroot/trusty_chrome personality=linux ... union-type=aufs union-mount-options=br:/srv/chroot/trusty_chrome.aufs=rw:/srv/chroot/base/trusty_amd64=ro Basically, the overlay and underlay directory is specified in the mount option. While man schroot.conf hints that they could also be determined by keys union-overlay-directory and union-underlay-directory, while I can not enter chroot properly with these options. More precisely, if I use the following conf, [trusty_chrome] description=Ubuntu 14.04 Trusty running Chrome and Adobe Flash directory=/srv/chroot/trusty_chrome personality=linux ... union-type=aufs union-overlay-directory=/srv/chroot/trusty_chrome.aufs union-underlay-directory=/srv/chroot/base/trusty_amd64 I'll encounter errors E: 20copyfiles: cp: cannot create regular file '/var/lib/schroot/mount/trusty_chrome-cb1db93d-c07c-4c2d-bef2-f5025358c2b3/etc/resolv.conf': No such file or directory E: trusty_chrome-cb1db93d-c07c-4c2d-bef2-f5025358c2b3: Chroot setup failed: stage=setup-start when try to enter this chroot. So the question is, how could I configure schroot using aufs by keys union-overlay-directory and union-underlay-directory. Moreover, when I list all chroot managed $ schroot -l chroot:trusty_chrome ... source:trusty_chrome ... I'll find two entries for each chroot using aufs. Is source:blabla a chroot? I can't enter them by schroot. I'm using schroot (Debian sbuild) 1.6.10 (04 May 2014) in Ubuntu 14.10.