MAAS 2 introduced a change in the maas-proxy service, which is its own proxy server.
If an upstream proxy is specified in the MAAS2 settings tab, it will *disable* its own maas-proxy service.
Autopilot has this bit of code in _get_cloud_config() in canonical/landscape/model/juju/jobs.py:
apt_http_proxy = "http://{}:8000".format(maas_server.get_address())
This will make deployments fail if an upstream proxy was configured in MAAS2, because maas-proxy won't be running anymore on the MAAS2 server and nothing will be listening on port 8000 there.
To reproduce the problem, just add something to the upstream proxy setting, save, wait about a minute while tailing /var/log/syslog and/or /var/log/maas/maas.log and you shall see the mass-proxy service being terminated.
Hi Andreas,
MAAS never supported such configuration. MAAS, as in previous releases, works in two ways:
1. if no external proxy specified, MAAS would use maas-proxy. This means two things:
1.1 MAAS would use maas-proxy to download images.
1.2 MAAS would tell machines to use maas-proxy.
2. if external proxy specified, MAAS wouldn't use maas-proxy.
2.1 MAAS would use external proxy to download images.
2.2 MAAS tells machines to use external proxy.
That said, the only relevant change in MAAS 2.0 in comparison to previous versions of MAAS, is that MAAS does tracking to the services it runs and makes sure that a service is ON or OFF depending whether MAAS is making use of it or not. As such, since (2) is being used, MAAS will correctly stop maas-proxy.