virt-builder

Posted Jun 29, 2018 7:29 UTC (Fri) by rwmj (subscriber, #5474)
In reply to: virt-builder by andrewsh
Parent article: Introducing debos, a versatile images generator

Effectively what's the difference? The templates are built from scratch (using distro installation tools like Anaconda and debian-installer) and then hosted somewhere, and the final step is to "sysprep" them (remove UUIDs, change passwords). The outcome is exactly the same.

Virt-builder can build an image in about 15 seconds if the template is cached locally.

virt-builder

Posted Jun 29, 2018 8:31 UTC (Fri) by puchalakd (subscriber, #28036) [Link] (2 responses)

I guess the biggest difference is that debos can automate building of images so they can be used by virt-builder. :)

virt-builder

Posted Jun 29, 2018 9:27 UTC (Fri) by rwmj (subscriber, #5474) [Link] (1 responses)

That's not wrong actually :-) debian-installer is quite difficult to automate. Unlike kickstart (as used by RPM) if a setting is missing in a d-i preseed file then it will interactively stop and ask for it rather than just carrying on with a suitable default.

virt-builder

Posted Jun 29, 2018 17:30 UTC (Fri) by smcv (subscriber, #53363) [Link]

As far as I'm aware, debian-installer was designed as an interactive installer and had non-interactivity glued on afterwards. The main use-case for preseeding is to fill in organisation-specific defaults, while leaving per-machine variation to be prompted for interactively. For totally non-interactive installation, it's probably the wrong tool. (It's also not particularly fast, and uses cut-down tools to fit in minimal RAM, which is probably not a great trade-off this decade.)

debos and debian-installer both use debootstrap to make a minimal installation, then add more packages and configuration afterwards. Various alternatives to debos are also debootstrap-based:

* vmdb2 and the discontinued vmdebootstrap are similar to the debos code paths that produce an image
* FAI is an installer like debian-installer rather than an image-builder, but non-interactive
* mkosi is somewhat less general than debos, with a focus on VM and container images rather than images for real hardware
* lxc images are container-specific
* Docker images are container-specific
* schroot/sbuild tarballs or template directories are "container"-specific (chroot rather than container, really)
* pbuilder tarballs are "container"-specific (chroot rather than container)

virt-builder

Posted Jun 29, 2018 9:40 UTC (Fri) by andrewsh (subscriber, #71043) [Link]

Debos does not use the distribution-provided images at all.