this derivation will be built:
  /nix/store/cbilf79fx9vzd70n1xs81xp0qa0iirq0-vm-test-run-pg_cron.drv
cannot build on 'ssh-ng://builder@mac-linux-builder': error: failed to start SSH connection to 'mac-linux-builder'
Failed to find a machine for remote build!
derivation: cbilf79fx9vzd70n1xs81xp0qa0iirq0-vm-test-run-pg_cron.drv
required (system, features): (aarch64-linux, [kvm, nixos-test])
3 available machines:
(systems, maxjobs, supportedFeatures, mandatoryFeatures)
([aarch64-darwin], 2, [apple-virt, big-parallel, kvm, nixos-test], [])
([aarch64-linux], 4, [benchmark, big-parallel, kvm, nixos-test], [kvm])
([aarch64-linux], 8, [benchmark, big-parallel], [])
error: Cannot build '/nix/store/cbilf79fx9vzd70n1xs81xp0qa0iirq0-vm-test-run-pg_cron.drv'.
       Reason: platform mismatch
       Required system: 'aarch64-linux'
       Current system: 'x86_64-linux'