Using RPMs for installation on embedded system images

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I'm trying to use RPMs to install public and private software into disk images that are eventually written to the boot flash of Linux based embedded systems.

My current methodology is to mount the image (/mnt/foo) read/write on a CentOS 6.5 box and use the rpm --installroot=/mnt/foo option. There are two problems:

  1. --installroot=/mnt/foo appears to chroot into /mnt/foo, meaning that when the post install scripts run /bin/sh (etc.) they're actually using /mnt/foo/bin/sh (etc.) That's sort of workable if the target architecture is the same as the installation box but gets very messy if its not. I'm interested to hear if someone has solved this before.

  2. At a higher level it would be nice to use yum or apt-get or ??? to handle package dependencies and repositories. yum is the obvious choice on CentOS but it has a weak grasp of non-native architectures and would likely require some hacking. apt-get looks more promising in that department but in truth I've never used it and my attempts to install it on CentOS 6.5 have left me in dependency hell.

This seems like a problem someone would have hit before but unfortunately everything I can find about RPMs and embedded systems assumes identical processor architectures.

Bottom line, I need to use RPMs to install software to a Linux image that will be the boot disk for a embedded system. Other than doing the rpm install as part of the image installation on the embedded system (our installation time is already a big problem) I'm open to just about anything.

Any suggestions will be gratefully received.

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linuxembeddedrpmyumapt-get
You can try modifying the anaconda-ks.cfg file and add that to a repo, that way with future installations you can add stuff such as the RPMs you need installed on the OS - ryekayo
yum has an --installroot option and you might be able to use --setopt to manually set basearch/etc. There's also repotrack which supports an --arch flag which might let you use the dep tracking to download the RPMs and then use rpm to install them to get around yum a bit. - Etan Reisner

1 Answers

1
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Have you tried using some continuous build system like Jenkins? You can use that to easily set up build hosts on any architecture/platform you like, so long as that platform has some basic tools (like ssh).

You could use a combination of the --installroot flag mentioned by other commenters, alongside of some VMs setup as build hosts in Jenkins in order to install your RPMs in a specific directory while avoiding any platform/architecture issues.

I'm not sure what your specific requirements are, but, depending on how far you are willing to go... RPMs are just compressed CPIO archives with a header, so you could use rpm2cpio piped to cpio to extract the files in the RPM. You can then extract the postinstall scripts using rpm -qp --scripts filename.rpm and run them yourself. The downside to this, is of course, that you lose a lot of the benefit of using RPM/yum in the first place like the automatic installation of dependencies, and so on.