Device mgmt: identity, communication with backend, monitoring, debugging, onboarding, updates, EOL, secure tunnel (VPN/SSH)
Fleet mgmt = devices in aggregate: scheduled updates (waves), alerting, integration with other services, authentication
No open source solutions for any of this exist. Doesn’t need to be integrated even, it could be something built from components.
Some people from mender were there. They said that mender, even though open core, would accept PRs for features that are currently closed but implemented (differently) by the community. To be taken with a grain of sand of course.
Azure IoT Hub looks open source, but it’s actually just a bunch of huge blobs that are dropped.