We should verify that an images build with opkg/rpm/dpkg are all identical. The package-manager image feature will need to be disabled so that the package manager itself and the the database doesn't cause changes. Do the diff with diffoscope so that we get nice reports showing the changes.
Comparing core-image-minimal built with opkg vs rpm there are a few differences: /etc/shadow and /etc/gshadow differ around the systemd users (bug 14139) /var/cache/ldconfig/aux-config can't be reproducible, as apparently the keys include inodes. If true we shouldn't generate the file at build time anyway. Diffoscope can be told to ignore this file with --exclude=./var/cache/ldconfig/aux-cache opkg leaves some empty directories /var/(lib|cache)/opkg.
Regarding the aux-cache, confirmed that it isn't suitable to be generated on the host as the hash keys include inodes: https://sourceware.org/git/?p=glibc.git;a=blob;f=elf/cache.c;h=c241c17ef9061a7c5ef41fd49dbb9dd624466c76;hb=HEAD line 545.
aux-cache is deleted from images in 67c1ceb193130fcb30853c2cd1a6ef33a814886e. opkg package management is deleted from images in 2209cef2cbe5fbdd5562f13f84ae2a3935f4fb61. Just bug 14139 left and then a selftest can be integrated.
Moved en masse from 4.2 to 4.3 by Randy.