Control: tag -1 wontfix Hi,
TLDR: there is no one-size-fits-all solution and mmdebstrap tries to do what debootstrap does. Usually reproducibility is required when mmdebstrap is run from a script and in that case, adding a hook which does the right thing is easy and documented with examples in the man page. Quoting Johannes Schauer Marin Rodrigues (2023-06-17 21:34:48) > Quoting Josh Triplett (2023-06-17 20:37:47) > > mmdebstrap has a couple of places in which it copies host configuration into > > the bootstrapped system. For instance, it puts the host's hostname into > > /etc/hostname, and copies in the host's /etc/resolv.conf. Please consider > > providing a single option that suppresses all current and future uses of the > > host configuration, to make it easier to build reproducible installations. > > > > The manpage mentions using a customize-hook to handle those two files, > > but given the common need for reproducible installations, it'd be nice > > to have this become simpler and standardized. > > you are right, mmdebstrap only creates bit-by-bit reproducible output if run > from the same host because of these two files it copies in. You are right in > that it should be easier to prevent those two files from messing up > reproducibility. > > The next question becomes: what should be done about /etc/hostname and > /etc/resolv.conf? What should their reproducible content be? > > Or should they just be deleted? > > You are not the only one who wants such an option: > > https://gitlab.mister-muffin.de/josch/mmdebstrap/issues/26 > https://gitlab.mister-muffin.de/josch/mmdebstrap/issues/33 > > As I've explained in the first of above issue, I'd rather add a hook than a > command line flag because all instances that I can come up with where you want > to run mmdebstrap to create bit-by-bit reproducible output, you run it from a > script and not manually type the command from the terminal. Can you confirm > this? I would like to suggest to those who run into this bug to try and convince debootstrap maintainers to improve reproducibility and no longer copy in /etc/hostname and /etc/resolv.conf. I fear this is not going to happen because it's just too convenient to have these two files get copied from the host. The man page now contains quite a bit of documentation about what mmdebstrap does and what to do to change its behaviour: > Remove files that make the result unreproducible and write the empty string to > /etc/machine-id if it exists. This can be disabled using > --skip=cleanup/reproducible. Note that this will not remove files that make > the > result unreproducible on machines with differing /etc/resolv.conf or > /etc/hostname. Use a --customize-hook to make those two files reproducible > across multiple hosts. See section "SOURCE_DATE_EPOCH" for more > information. > > [...] > > Note that for debootstrap compatibility, mmdebstrap will copy the host's > /etc/resolv.conf and /etc/hostname into the chroot. This means that the > mmdebstrap output will differ if it is run on machines with differing > /etc/resolv.conf and /etc/hostname contents. To make the result reproducible > across different hosts, you need to manually either delete both files from > the > output: > > $ mmdebstrap --customize-hook='rm "$1"/etc/resolv.conf' \ > --customize-hook='rm "$1"/etc/hostname' ... > > or fill them with reproducible content: > > $ mmdebstrap --customize-hook='echo nameserver X > "$1"/etc/resolv.conf' \ > --customize-hook='echo host > "$1"/etc/hostname' ... If you are interested in bit-by-bit reproducible mmdebstrap output, then you are probably running it from a script and in that case, just add the hooks which do what your use-case requires. Thanks! cheers, josch
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