# Overview

So we have some machines(we call those "nodes")
and each of those nodes runs (1) a nomad client; and (2) a consul client.
Also, all these nodes are in a wireguard network.

nomad is responsible for actually deploying the servers on an available machine.
actually the Nomad *Server* has state and knows what all clients are doing,
while Nomad *Clients* are just doing what the server tells them to, like deploying
a job.

A job is just a docker container, or the smallest deployable unit ig.

the same server-client-relationship exists with consul. Here, Consul's main
purpose is to resolve hosts. A job registers itself (via a Consul Client) like
"hey im a postgres server and i run on 10.0.2.1:5432" and then the Consul Master
updates its catalogue: "oh so postgres is 10.0.2.1:5432" and then in our jobs, we
can just use "postgres.service.consul" and it resolves to 10.0.2.1:5432 so thats cool.

Now wireguard is needed because while consul resolves hostnames, it doesn't help
us connect to the resolved IPs. With a single node, that's fine but if we want to
access a service on another node, we need wireguard(or something similar).
Actually if we run all nodes in the same network and it'd be fine without.

## Most Basic Implementation

- single node
- runs `dnsmasq -d`, `nomad agent -dev`, and `consul agent -dev` as root
- /etc/nomad.d/consul.hcl:
    consul {
      address = "127.0.0.1:8500"
    }
- /etc/dnsmasq.conf:
    server=/consul/127.0.0.1#8600
- all jobs define a consul service
- TODO: make dns/connect work


## useful stuff

- `nomad job run <job>.hcl`
- `consul catalog services` <- list registered services
- http://localhost:4646/ui/jobs <- web UI accessible after `nomad agent -dev`
- https://developer.hashicorp.com/nomad/docs/configuration
- https://developer.hashicorp.com/nomad/docs/job-declare/service-discovery

## Storage/SPOT

the papermc container already copies all files in /mnt/*
to /data, so it's easy to add overwrites.
in ./lobby.nomad.hcl I just use a prestart container that downloads the plugin
to a temporary volume that is then used as /mnt.
A lot of boilerplate and it's also not easy to add other files.
Ideally, we'd just copy a whole directory over sftp. it would look
like this:
    /.gitignore <- data
    /Makefile <- downloads plugins specified to /data/plugins
    /static <- static files that are copied by make to /data
But ig that wouldn't play nice with CI/CD...

Also currently we need to duplicate a lot of this boilerplate btw.