Juju run runs as root, not 'ubuntu'

[Aaron Bentley]

The docs say:
  If the target is a machine, the command is run as the "ubuntu" user on
  the remote machine.

But actually the command is run as root:
$ juju run --machine 0 whoami
root

Although the ubuntu user can sudo, this is still surprising and potentially dangerous behaviour.

The release notes do not show this change in behaviour. If root is intended, the command help and release notes should be updated.

[Tim Penhey (thumper)]

Juju run used to use ssh from the controller machine and would connect as the ubuntu user using the juju system identity ssh key.

The way run worked was changed during the 2.0 cycle to go through the actions mechanism. Obviously when it runs now it is running as the user running the machine agent.

[Aaron Bentley (abentley)]

If root is intended, the command help and release notes should be updated.

[Anastasia (anastasia-macmood)]

Marking as Won't Fix for 2.0.x as no further 2.0.x releases are planned.

[John A Meinel (jameinel)]

https://github.com/juju/juju/pull/7090

[John A Meinel (jameinel)]

Given things like "juju run --unit" need to run in a hook context, which means it is inherently running as root anyway, it makes the most sense for "juju run --machine" to also run as root. If they want to drop their permissions they can always "su - ubuntu" as part of the script.

I updated the CLI help text to indicate this and added an Issue against juju/docs that we should make sure any other documentation also indicates it is root.

[Tim Penhey (thumper)]

@Peter, this bug is about 'juju run' command, and not the jujud agents.