Starting with Falco 0.8.0, falco officially supports the notion of a default rules file and a local rules file. This has previously been supported by running falco with multiple -r arguments. In 0.8.0, we’re formalizing this notion to make it easier to customize falco’s behavior but still retain access to rule changes as a part of software upgrades. Of course, you can always customize the set of files you want to read by changing the rules_file option in falco.yaml.

The default rules file is always read first, followed by the local rules file.

When installed via rpm/debian packages, both rules files, as well as the falco configuration file, are flagged as “config” files, meaning they are not overridden on package upgrade/uninstall if modified.

Default Rules File

The default falco rules file is installed at /etc/falco/falco_rules.yaml. It contains a predefined set of rules designed to provide good coverage in a variety of situations. The intent is that this rules file is not modified, and is replaced with each new software version.

Local Rules File

The local falco rules file is installed at /etc/falco/falco_rules.local.yaml. It is empty other than some comments. The intent is that additions/overrides/modifications to the main rules file are added to this local file. It will not be replaced with each new software version.