Need a documented solution to the undercloud being behind a proxy

[Steve Baker]

When the undercloud is behind an http proxy we need to document how to set the proxy environment variables for a successful undercloud install and overcloud deploy.

I can install the undercloud when http_proxy, https_proxy and no_proxy are set in the undercloud /etc/environment, however a fix is needed for overcloud deploy because these environment variables need to be set inside mistral_executor too.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/640925

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/640925
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=9cb715a5e766909ad8ac4d2d949cc3c141d7923f
Submitter: Zuul
Branch: master

commit 9cb715a5e766909ad8ac4d2d949cc3c141d7923f
Author: Steve Baker <email address hidden>
Date: Tue Mar 5 15:27:54 2019 +1300

    mistral-executor include host /etc/environment

    The undercloud host file /etc/environment will be documented as where
    proxy environment variables will be set when the undercloud is behind
    a proxy server.

    These variables also need to be set inside the mistral_executor
    container for the pre-deployment image prepare to access external
    registries. This change will make that possible without any further
    changes required from the deployer.

    Change-Id: Ie8924833a2410eea096fda955c8c6df9b1f0e207
    Partial-Bug: #1818590