A hosted runner of the ubuntu-24.04 pool is not promised nested virtualization, and
3 of the 16 suites of run 42182554717 failed the check of /dev/kvm. rerun-no-kvm.yaml
could not help: a workflow_run workflow runs only from the default branch, where the
file is not, and a run cannot rerun its own failed jobs while it is in progress.
The step "Enable KVM" of the nix action is now the only one that enables KVM
(enable_kvm of install-nix-action is off), runs before the disk and the install,
waits for udev to settle and polls /dev/kvm for 30 seconds instead of testing it
once, 42 ms after an asynchronous udevadm trigger, and prints what tells a missing
device from a rule that was not applied yet. With defer-no-kvm a host without KVM
is an output, not a failure.
_vm.yaml calls _vm-attempt.yaml up to three times: the suites that found no KVM are
listed through the artifacts of the run and run again on new machines, and the last
attempt fails them. vm-fast and vm-slow are calls of it. rerun-no-kvm.yaml is
removed.
A NAR of 460 MB was cut by the edge of the cache ("Stream error in the HTTP/2 framing layer") and the
resumed request failed the same way, so the job kwin-events failed before its VM test started. With
fallback = true Nix builds the derivation from source when a substitute cannot be downloaded: one dropped
connection costs minutes of compiling in that job, not the job. HTTP/2 is left at its default: nothing
shows that turning it off prevents the error.
An unquoted ": " inside the description made action.yaml invalid YAML ("mapping values are not allowed in
this context"), so every job that uses the action would have failed at its first step.
The write token goes to cachix-action on a push (master and the temporary komomono
trigger, without naming either), a manual run and a schedule; a pull request, a fork
and the merge queue only read. The flake-lock update goes through the nix action too,
and the nixpkgs canary reads the cache but never pushes (push: "false" replaces
cache: "false").
docs(ci): the write rule, the read-only path and a checklist for the first push to
komomono.
LGUG2Z