Declaring chart dependencies
Chart dependencies are used to install another chart’s resources that a Helm chart (referred to as the parent chart) may depend on. We saw an example of chart dependencies in action when we installed WordPress in Chapter 3, Installing Your First App with Helm. When we installed WordPress, we used the wordpress chart to install both the WordPress application instance and a MariaDB backend. You may be surprised to learn that the MariaDB database that was installed was not a native WordPress chart resource – it was a dependency! We can confirm this fact by running the helm show chart command to view the dependencies declared in the wordpress Chart.yaml file:
$ helm show chart bitnami/wordpress --version 12.1.4
In the output, you’ll see the dependencies map, as follows:
dependencies: - condition: mariadb.enabled name: mariadb repository: https://raw.githubusercontent.com/bitnami/charts/archive-full-index...
