Synchronizing the state between the edge and the cloud
The HBS hub device, if made into a real product, would connect with local devices over a network protocol and proxy telemetry and commands with a cloud service. In the previous chapter, we used components running on our hub device to interface with local hardware interfaces on the Raspberry Pi Sense HAT.
This makes sense when the hub device communicates with hardware over serial interfaces, but when communicating over a network, those appliance monitoring kits won't really be software components running on the hub device using the Greengrass IPC interface to exchange messages. Instead, they may use a network protocol such as Message Queue Telemetry Transport (MQTT) to exchange messages with the hub device over Wi-Fi or Bluetooth.
In this section, you will deploy new managed components for connecting to leaf devices over MQTT and synchronize the state of a leaf device's telemetry to the cloud.
