/operations-deployment-charts

Helm deployment charts for Wikimedia. Mirror from https://gerrit.wikimedia.org/g/operations/deployment-charts - our actual code is hosted with Gerrit (please see https://www.mediawiki.org/wiki/Developer_access for contributing)

Primary LanguageSmartyGNU General Public License v3.0GPL-3.0

Wikimedia Helm Charts

This is the repo that powers https://helm-charts.wikimedia.org/stable/.

Here you will find the various helm charts the Wikimedia Foundation uses in developing software and deploying it to production.

Creating a new chart

If you want to create a new chart use the create_new_service.sh script, test it and upload a change to Gerrit. Then wait for a review.

Template names are global

If two separate charts have templates with the same names and are deployed in the same release, the last definition of the template will be used for both charts. Please take this into account when designing new charts.

Since the main _helpers.tpl file is shared across all charts, you will probably have to ship a different template helpers file that contains your own templates and use it accordingly.

Other stuff

The values.yaml files provided by any chart are defaults and their purpose is to help deployment under development clusters. Actual values used in production are not kept here.

The _scaffold/ directory is used by the create_new_service.sh script, it's best to leave it alone.

Updating a Chart

If you want to update an existing chart then changes should be made to it in the charts/ directory.

The changes should include incrementing the chart's version in the respective Chart.yaml file.

The resulting files and changes should then be uploaded to Gerrit for code review.

Linters and tests

Charts are linted using helm lint and helm template; the resulting templates are also checked to ensure they produce valid YAML files.

Many charts use feature flags like monitoring.enabled: true to include or omit artifacts from the generated configuration. These optional features can and should be tested by providing values overrides for each feature flag. The tests will run the lint and template steps once with just your values.yaml data and then again for each YAML file in the chart's .fixtures/ directory.

In addition to the basic linting and template validation, all service deployments under helmfile.d/services are checked by each test run. Settings expected to be loaded from puppet managed files under /etc/helmfile-defaults during a deployment are not present in the testing environment. You can provide necessary values for testing by creating a helmfile.d/services/$SERVICE/.fixtures.yaml file to simulate production data.

NOTE: During the integration testing of helmfile.d/services charts are pulled from the merged and deployed charts in the chart repository. For this reason, changes to a chart and related changes to its helmfile configuration must be uploaded to gerrit and tested separately. Hemlfile changes for a new chart version must be tested after the chart changes have been merged and updated in the chart repository.

License

While the helm charts specification allows for a per chart license to be specified, we are following a more strict approach. All of the charts in this repo MUST have the exact same GPL-3.0-or-later license. See our LICENSE file for full license information.