$ sudo cat /etc/sudoers.d/mic-smoser 
[sudo] password for smoser: 
# smoser let all users in lxd group run mic lxd: mchroot
Cmnd_Alias      MIC_LXD_CHROOT = \
                /usr/bin/mount-image-callback lxd\:* mchroot, \
                /usr/bin/mount-image-callback lxd\:* mchroot *, \
                /usr/bin/mount-image-callback lxd\:* uns-switch, \
                /usr/bin/mount-image-callback lxd\:* uns-switch *
%lxd ALL=(ALL) NOPASSWD: MIC_LXD_CHROOT