Understanding Servers and Sets

Servers and Sets can be configured for MQTT Transmission and MQTT Engine

Servers

The Servers tab allows you to configure a list of the MQTT Servers that the MQTT module should connect to.

Multiple MQTT Servers can be configured - often times more than one will be configured to handle fail-over in redundant or geographically distributed systems. 

Sets

The Sets tab allows you to configure server sets.

Each set represents a logical grouping of MQTT servers. 

When a set is referenced by a Transmitter configuration or an MQTT Engine configuration, a single connection to one of the servers in the set will be maintained. The other servers will act as failover in the case that a connection with the first is lost.

Servers will not be prioritized to force a connection to one server if multiple are available.

Server sets cannot have common elements meaning that a single MQTT server cannot be in more than one set.

Example

In the configuration below we have setup two server sets - one has two server configurations associated with it and one has three server configurations.

We have two Transmitter configurations each associated with one of the server sets.

A single connection is made to the first available server in each set. If this server becomes unavailable, MQTT Transmission will attempt to establish a connection with the next server in the set. If unsuccessful, it will continue to walk through the servers in the set until a connection can be made.