Which MQTT broker (self hosted vs. Mosquitto or others)?
Which Linux? Command line or with Desktop GUI?
See Best Linux Version to Node-Red for a discussion on this. I am surprised that you did not see that post, presumably you did search the forum before asking the question.
Whether you want a gui or command line install is up to how you want to use it.
Mosquitto. Self hosted.
Many thanks
Which linux has been addressed many times. I won't come back to it.
If you need 24/7 operations, then having a redundant broker is (for me) key.
Mosquitto is an excellent choice, unfortunately, the free and open source version can't be clustered.
For clustered broker, EMQX as free and open source is an option.
RabbitMQ for MQTT only is very complex.
VerneMQ is a very good choice, but, you'd have to pay for a licence.
In front of those, you will need a (redundant) load balancer.
HAProxy is a good option.
My 2 cents...
Can you explain why? What is the benefit?
Well, your unique instance of broker may fail (the software, the host were it runs...), it is a SPOF.
To avoid that, having redundancy active/standby or else is key.
For MQTT, the clustering is a way to address 24/7 operations.
But if your node-red has failed then what is the point of having a standby mqtt broker? So that is also a single point of failure, as is your influxdb service.
I would agree that if you really want guaranteed uptimes, you need to think about end-to-end resilience.
But as usual, this is totally dependent on the background requirements - which haven't been offered to us as yet.
So we really need to ask for more background info before recommending something.
In my app, I have an MQTT cluster (VerneMQ), Redis in cluster, and NodeRed runs in docker and I have two instances running in actve/passive mode.
I agree with Julian, all is very context dependant...
