It turns out ansible already provides info about the default network
interface in the ansible_default_ipv4 dict variable, so we can use that
instead of using the 'ip route show' command.

On Ubuntu 16.04, the default networks interface is not always called
eth0, depending on the hardware. The name of the default network
interface on some VM types on AWS is ens3, for example.

Determine the interface name using ip route command instead of
hardcoding to eth0.

Also, /etc/network/interfaces.d/<interface-name>.cfg files no longer
exist in Ubuntu 16.04. Use a script in /etc/network/if-up.d to
adjust the MTU value at startup instead.

Disable app preload in gunicorn for LMS & Studio.

Since the earliest days of edX, we've run gunicorn with preload_app as
True. This was primarily because the first handful of courses were using
the XMLModuleStore, which was extremely slow to initialize because it
had to read entire courses from disk and load them into memory at
startup.

XMLModuleStore courses stopped being created with the introduction of
Studio, and we've long since removed them from edx.org. Note: This
should not be confused with importing courses that are authored in XML.
XMLModuleStore courses are courses who use the disk instead of Mongo
for content persistence, and require a server restart for content edits
to show.

This commit sets things back to how Django is more commonly deployed
with gunicorn. It will make server startup time somewhat more expensive
because each worker process does init work, but it should make it
easier to safely enable features like database connection pooling
without having to worry about shared resources.

[PERF-305]

Quiet an ansible deprecation warnings

[DEPRECATION WARNING]: Instead of sudo/sudo_user, use become/become_user and
make sure become_method is 'sudo' (default).
This feature will be removed in a
future release. Deprecation warnings can be disabled by setting
deprecation_warnings=False in ansible.cfg.

Apply changes from the previous task.

Rabbit will only use 40% of RAM, allow this to go up

Just causes confusion with notifier.yml

Without this, resolv.conf won't be updated in our environment until the
lease expires and dhclient reruns.  The -n should prevent it from
*actually* changing interfaces, and instead just updates the conf files.

The linked documentation comes out ao .7 for a t2.large
We can also prevent rabbit from going to disk until more memory
is full, but that isn't needed right now.

Attempt to give the version tag attached by the pipeline a better name

LEARNER-406

infrastructure for building an AMI for a loadtest driver jenkins worker

The CD infrastructure shouldn't clobber the tag added by the underlyi…

* Add a new ansible role "loadtest_driver" for setting up any instance
  for running load tests.
* Make the existing "locust" role depend on loadtest_driver and pull out
  the redundant tasks.  The "locust" role is outside of the AMI-building
  code path, but we do use it for something else and want to keep common
  tasks shared.
* Make the "jenkins_worker" role depend on the new "loadtest_driver"
  role.
* Create a new ansible playbook for setting up loadtest drivers.
* create a new packer script to build an AMI for loadtest drivers.

matrix-auth was being overridden by Jenkins (down to 1.1)

https://github.com/jenkinsci/job-dsl-plugin/wiki#release-notes

We don't use any of the plugins impacted by the migrations from 1.50
to 1.52, but performing some manual testing of jobs.
https://github.com/jenkinsci/job-dsl-plugin/wiki/Migration#migrating-to-152

This appears to be because it wasn't pinned and the shipped version
of the plugin won.  We have pinning code in jenkins_master that we
can use, but we have to copy down that list to add ours (ansible
doesn't allow "recursive references" of a variable passed back to
itself.

Continue process of trying to group plugins and their deps.

Update sandbox base AMI.

pull out protocol from FORUM_ELASTICSEARCH_URL

Add newrelic to jenkins workers.

Deploy edx-themes:master instead of edx-themes:release

We want the release pipelines to deploy edx-themes:master to avoid
the additional step of merging edx-themes:master to edx-themes:release
in order to deploy changes to edx-themes.

WL-1018

This Dockerfile is based on the official image (rather than built from scratch by us) and includes the elasticsearch-head plugin.

ECOM-7552

No need to create different replica user

find-exec won't expand wildcards

Exclude Enterprise API from auth.

ubuntu-restricted-extras requires multiverse

Configure ca-certificates for java in go-agents