Upgrade the versions of sub-charts used in our Helm chart

The basehub helm chart that 2i2c deploys on their hubs, depends on several upstream helm charts. This chart needs to be kept up-to-date with the upstream releases so that the communities we serve benefit from the latest features and bug fixes.

Before rolling out a new version of a sub-chart to all of the hubs, we need to make sure that it works as expected. Although manual testing is important, things might still break in production, under high user activity, exposing edge cases that were not considered during testing.

This is why it’s important to be able to roll out new versions of sub-charts gradually, starting with a small number of hubs, and then extend it to others, as we gain confidence that the new version is working as expected.

Bumping the version of a helm sub-chart for all hubs¶

To bump the version of a sub-chart, we need to edit the Chart.yaml file of the basehub chart, located at helm-charts/basehub/Chart.yaml and update the version of the sub-chart we want to upgrade.

This will bump the version of the sub-chart for all hubs that use the basehub chart.

Bumping the version of a helm sub-chart for a specific hub¶

1. Create a custom Chart.yaml file¶

No matter if the hub is a basehub or a legacy daskhub, the override file will override the basehub’s Chart.yaml file. The script will recognize that it’s a daskhub from it’s config and will do the correct thing.

Example staging-chart.yaml

• copy the contents of the original helm-charts/basehub/Chart.yaml file into staging-chart.yaml

• update the version of the sub-chart you want to bump.

2. Configure the hub to use the custom Chart.yaml file¶

Edit the cluster.yaml file of the cluster, located at config/clusters/<cluster-name>/cluster.yaml and add the path to a custom Chart.yaml file under chart_override.

Example:

hubs:
- name: staging
  display_name: 2i2c staging
  domain: staging.2i2c.cloud
  helm_chart: basehub
  helm_chart_values_files:
  - basehub-common.values.yaml
  - staging.values.yaml
  - enc-staging.secret.values.yaml
  chart_override: staging-chart.yaml

In this example, the staging hub will use the staging-chart.yaml file in the config/clusters/<cluster-name> directory, to override the default Chart.yaml file of the basehub chart.