Helm Strategies

1. Automatically Roll Deployments

Often times ConfigMaps or Secrets are injected as configuration files in containers or there are other external dependency changes that require rolling pods. Depending on the application a restart may be required should those be updated with a subsequent helm upgrade, but if the deployment spec itself didn't change the application keeps running with the old configuration resulting in an inconsistent deployment.

The sha256sum function can be used to ensure a deployment's annotation section is updated if another file changes:

kind: Deployment
spec:
  template:
    metadata:
      annotations:
        checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
[...]

info

If you're adding this to a library chart you won't be able to access your file in $.Template.BasePath. Instead you can reference your definition with {{ include ("mylibchart.configmap") . | sha256sum }}.