Optional services about devops

[blokovi]

Let's start with making non-core services optional. For now, that are influxdb reader & writer (and influxdb database itself). All non-core services we will add later should be optional also.
Influx services will be enabled with --set influxdb.enabled=true

[nmarcetic]

@blokovi Agree, that make sense. Not sure about UI, maybe is good idea to have it as part of Core (its not add-on, it's just in another repository). Although I think Mainflux should stay lightwate and client agnostic I think it would be good to run UI as part of Core in helm chart.

[blokovi]

I agree, umbrella charts sounds good. I have already make add-ons (influxdb and bootstrap) optional in PR #50 that will close this issue when it's merged. We will continue conversation about umbrella charts in new issue.

[nmarcetic]

@blokovi Great! I saw PR #50 Can we do the same for Twins (must-have) and OPC-UA (nice to have) later?

[blokovi]

On second thought, bootstrap and ui are also non-core, they must be optional also if we follow this rule, I will make them optional in PR #50
Twins and opcua are work-in-progress, and PR will be sent today, but that is another issue - #21

[nmarcetic]

@blokovi I am also thinking about chart dependencies and umbrella charts. Thing to think about in for #later or next stage of refactoring,

We can scope Core services and make mainflux/core chart as the main chart. Creat micro charts for each add-on that we have and mark them with a condition: optional, then import them in core chart. Each micro chart will have mainflux/core marked as a dependency (you can't run grafana add-on without core).
This way we will avoid hardcoded conditions like if/else in the chart, which grows all the time and will become hard to maintain.
We also get tagging and version management simpler.
People get install only core or upgrade only add-ons without touching core release. It's much more flexible.
It will be much easier to maintain and develop if we decouple it.
If you agree, maybe we can open an issue, market it as enhancement, and continue the conversation there?