Can I effectively use Consul for my use case : highly distributed IOT application

[Nirmal Thacker]

Hi

I'm evaluating Consul for the following requirements I have in my application:
1. Health monitoring and alerting for IOT devices geographically distributed
2. Dynamic configuration for these devices

Consul appears to be a great fit, given it does these two really well when I integrate consul-alert and envconsul.

I intend to have 3-5 consul servers in the cloud (Google Cloud for instance) and the devices, running as consul clients. Consul servers additionally have consul-alert daemon running and all consul clients run the target proc wrapped with envconsul for the second requirement.

However the difficulty in visualizing this is in the networking complexity:

1. Running consul servers on a public IP seems like a bad idea - or is it acceptable ? What sort of security issues must I be aware about?
2. Does having my consul servers and consul clients on a VPN help?
3. Is consul the right tool for this setup? What other alternatives could deliver my requirements for my environment?

Thanks
Nirmal

[James Phillips]

> 3. Is consul the right tool for this setup?

Hi, Consul probably isn't a good fit for this use case as the gossip
protocol expects to have a pretty good local network between all of
the agents in a cluster, and the agents need to be in a full mesh
because any agent can probe any other agent. Having devices all over
the world would definitely break that assumption (and the timing
assumptions) built into Consul, so I think your cluster would see a
lot of node health flapping. This is pretty baked into Consul's
design, so it would be hard to work w/o that.

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[Nirmal Thacker]

Thanks for responding James.

I intend to deploy consul over tinc (http://tinc-vpn.org/), a meshed VPN that can enable the gossip protocol to occur between consul clients, directly. Would that address some of the timing assumptions in Consul?

Nirmal

[Tyler Rivera]

Nirmal, if you haven't already, it might be worthwhile to look into using an MQTT broker to facilitate such a distributed system. This is core to both Google and AWS IoT platforms. 

[Nirmal Thacker]

Hi Tyler,

Thanks for responding and sharing MQTT.

With MQTT can I build an alerting system that is time sensitive like Consul does? For instance in Consul, we can configure health check scripts that run every so often and failed health checks can be tied into alerts and metrics using consul-alerts. So how would one do that using an MQTT system? As I understand it, the IOT devices themselves can frequently publish their health check to the broker, but how does a subscriber determine alerting if it hasn't heard from a device?

Thanks!
Nirmal

[Tyler Rivera]

This is probably outside the scope of this group, MQTT is simply a pub/sub broker. Many people will subscribe to a topic on MQTT and build alerting systems based on the messages they see on that topic.