Comment 1 for bug 1821045

With the right config set, once the machine has finished bootstrapping, I do see:
root@juju-50ff28-0:~# sudo snap get core -d
{
        "cloud": {
                "name": "unknown"
        },
        "proxy": {
                "http": "",
                "https": "",
                "store": "yFsGTy6qwkrVISeJI1JjU09v9Uxlc0Gf"
        },
        "refresh": {
                "hold": "2019-03-20T19:42:00.762131261Z"
        },
        "seed": {
                "loaded": true
        }
}

So the config is correct. I can also see that "snap install juju --classic --channel 2.5/edge" downloads at approx 100MB/s so it is clearly using the local snap store proxy.

We just need to configure that before we install juju-db.