bento/doc/reference.md

Environment variables

bento is using the following environment variables as configuration:

• BENTO_DIR: contains the path of a bento directory, so you can run bento commands from anywhere
• NAME: contains machine names (flake config or directory in hosts/) to restrict commands deploy and build to this machine only
• VERBOSE: if defined to anything, display nixos-rebuild output for local builds done with bento build or bento deploy

Self update mode

You can create a file named SELF_UPDATE in a host directory using flakes. When that host will look for updates on the sftp server, if there is no changes to rebuild, if SELF_UPDATE exists along with a flake.nix file, it will try to update the inputs, if an input is updated, then the usual rebuild is happening.

This is useful if you want to let remote hosts to be autonomous and pick up new nixpkgs version as soon as possible.

Systems will be reported as "auto upgraded" in the bento status command if they rebuild after a local flake update.

This adds at least 8 kB of inbound bandwidth for each input when checking for changes.

Auto reboot

You can create a file named REBOOT in a host directory. When that host will rebuild the system, it will look at the new kernel, kernel modules and initrd, if they changed, a reboot will occur immediately after reporting a successful upgrade. A kexec is used for UEFI systems for a faster reboot (this avoids BIOS and bootloader steps).

Track each host state

As each host is sending a log upon rebuild to tell if it failed or succeeded, we can use this file to check what happened since the sftp file last_time_changed was created.

Using bento status you can track the current state of each hosts (time since last update, current NixOS version, status report)