Switch provisioning at Dropbox is handled by a Pirlo component called the TOR Starter. The TOR Starter is responsible for validating and configuring switches in our datacenter server racks, PoP server racks, and at the different layers of our datacenter fabric that connect racks in the same facility together. Writing the TOR Starter on top of the ClusterOps queue provides us with a basic manager-worker queuing service.
We also have the ability to customize the queue to fit our needs in switch provisioning. The switch job table (shown below) is an extension of the basic job table. Similarly, the TOR Starter queue manager thread implementation is customized to queue switch jobs, and the TOR Starter worker implements all of the switch validation and provisioning logic.
Along with all of the switch job attributes, there are several tables that provide a comprehensive view of a switch job. As a switch job is running, the current state can be queried by a client and displayed in our user interface. After a switch job has completed, all of the job’s state is kept in the database and can be queried for reporting and analytics purposes.
Tables in the database also hold information related to each component in the switch such as its network uplinks, fans, and power supplies. All of the captured data from a switch is linked to a particular switch job.
Source: dropbox.com