### User story I would like to request this feature as an authenticated user, willing to use `debian_pipeline`-based workflows, that include enabled `autopkgtest` and `autopkgtest for reverse dependencies` tasks. I would like that those autopkgtest jobs run on the "minimal" backend supporting the restrictions found in the package's tests, i.e. `lxc` containers or `qemu` when `isolation-container` and `isolation-machine` are needed, respectively. For any other autopkgtest, running on the `unshare` backed should be enough. Taking the liberty of using openssh as example, the 1:10.0p1-1 version of that package includes [four autopkgtests](https://sources.debian.org/src/openssh/1%3A10.0p1-1/debian/tests/control/), all of them require `isolation-container`. And those autopkgtests are [skipped in the current debusine.d.n](https://debusine.debian.net/debian/developers/work-request/85182/) `upload-to-unstable`'s autopkgtest task, since it runs on the `unshare` by-default backend. With the proposed feature, I would like that such autopkgtest task runs on `lxc` (or `qemu`), making the autopkgtest task's outcome more meaningful. Moreover, openssh's systemd reverse dependency includes an autopkgtest that requires `isolation-machine`: https://debusine.debian.net/debian/developers/work-request/85195/. So it would be awesome if, under the `autopkgtest for reverse dependencies` tasks, systemd`s runs on the `qemu` backend. As far as I understand, there are currently no clear plans about how a regular user could override the settings defined in the workflow template. I think that a dynamic autopkgtest backend definition mechanism would help, especially if several people could prepare updates for a package during the lifecycle of a debian release (maintenance team, sec team, LTS/ELTS team), so the debusine pipeline could provide consistent results at each release-based workflow. ### Error handling ### Implementation plan ### Open questions ### Notes This issue description can be modified to integrate feedback from comments and from associated merge requests.