Recovering from a bad NixOS rollback
Sometimes the previous generation is not the one you want.
List available generations
nixos-rebuild list-generationsPick the generation number you trust, then switch to it.
Switch to a specific generation
sudo nixos-rebuild switch --generation 42A table of common rescue paths
| Problem | Quick path |
|---|---|
| Bad kernel | Boot an older generation from the bootloader |
| Broken service | systemctl stop unit then rollback |
| Lost secrets | Restore from SOPS backups before activation |
Remember
Rollbacks are only easy if you keep generations.
Set a reasonable configurationLimit on boot.loader.systemd-boot or GRUB so you do not erase your escape hatch.