[AIRFLOW-2601] Allow user to specify k8s config

[Noremac201]

This adds the ability in the Kubernetes operator to specify the config file, if it is different than default.

JIRA

• My PR addresses the following Airflow JIRA issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-2601

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it.
  • When adding new operators/hooks/sensors, the autoclass documentation generation needs to be added.

Code Quality

• Passes git diff upstream/master -u -- "*.py" | flake8 --diff

[kaxil]

Can you add some tests?

[codecov-io]

Codecov Report

Merging #3491 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3491   +/-   ##
=======================================
  Coverage   77.14%   77.14%           
=======================================
  Files         203      203           
  Lines       15123    15123           
=======================================
  Hits        11667    11667           
  Misses       3456     3456

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[Noremac201]

My Travis CI is passing:
https://travis-ci.org/Noremac201/incubator-airflow/builds/392010960

[dimberman]

Code-wise this looks fine to me. You could test this by adding a travis step that copies the kubeconfig to an arbitrary folder and then running a test that points to that arbitrary kubeconfig. Also it looks like your travis build is failing (might need to rebase)

[kaxil]

@Noremac201 Can you add the test @dimberman is suggesting? Once that is done I am happy to merge this.

[Noremac201]

I believe I've added the test that was asked for. If not let me know how I should've done it.
Travis passed on my branch:
https://travis-ci.org/Noremac201/incubator-airflow/builds/393725214

Thank you

[dimberman]

@Noremac201 Test looks good, I'm seeing the travis as failing but the failure looks unrelated to your changed.

@kaxil LGTM