there are currently four UUIDs that you can use: - hardware uuid (

uuid

): this is basically an ID found on the motherboard or something. it should persist re-installs of the OS. - ephemeral uuid (

ephemeral

): this is different every time osqueryd starts (useful for ephemeral instances or running many osquerys in one container for example) - database-stored uuid (

instance

): this is stored in rocksdb and should live for the life of the OS assuming the rocksdb database never gets deleted which may or may not be a reasonable assumption to make. if the OS is re-installed, this will not persist. - a specific value (

specified

): this is useful if you have robust configuration management and want to specify the uuid of each host manually via configuration.