helm-operator-integration.md

Integration with the Helm operator

You can release charts to your cluster via "GitOps", by combining Flux and the Helm operator (also in fluxcd/flux).

The essential mechanism is this: the declaration of a Helm release is represented by a custom resource, specifying the chart and its values. If you put such a resource in your git repo as a file, Flux will apply it to the cluster, and once it's in the cluster, the Helm Operator will make sure the release exists by installing or upgrading it.

Upgrading images in a HelmRelease using Flux

If the chart you're using in a HelmRelease lets you specify the particular images to run, you will usually be able to update them with Flux, the same way you can with Deployments and so on.

Note: for automation to work, the repository and tag should be defined, as Flux determines image updates based on what it reads in the .spec.values of the HelmRelease.

Flux interprets certain commonly used structures in the values section of a HelmRelease as referring to images. The following are understood (showing just the values section):

values:
  image: repo/image:version

values:
  image: repo/image
  tag: version

values:
  registry: docker.io
  image: repo/image
  tag: version

values:
  image:
    repository: repo/image
    tag: version

values:
  image:
    registry: docker.io
    repository: repo/image
    tag: version

These can appear at the top level (immediately under values:), or in a subsection (under a key, itself under values:). Other values may be mixed in arbitrarily. Here's an example of a values section that specifies two images, along with some other configuration:

values:
  persistent: true

  # image that will be labeled "chart-image"
  image: repo/image1:version

  subsystem:
    # image that will be labeled "subsystem"
    image:
      repository: repo/image2
      tag: version
      imagePullPolicy: IfNotPresent
    port: 4040

You can use the same annotations in the HelmRelease as you would for a Deployment or other workload, to control updates and automation. For the purpose of specifying filters, the container name is either chart-image (if at the top level), or the key under which the image is given (e.g., "subsystem" from the example above).

Top level image example:

kind: HelmRelease
metadata:
  annotations:
    flux.weave.works/automated: "true"
    flux.weave.works/tag.chart-image: semver:~4.0
spec:
  values:
    image:
      repository: bitnami/mongodb
      tag: 4.0.3

Sub-section images example:

kind: HelmRelease
metadata:
  annotations:
    flux.weave.works/automated: "true"
    flux.weave.works/tag.prometheus: semver:~2.3
    flux.weave.works/tag.alertmanager: glob:v0.15.*
    flux.weave.works/tag.nats: regex:^0.6.*
spec:
  values:
    prometheus:
      image: prom/prometheus:v2.3.1
    alertmanager:
      image: prom/alertmanager:v0.15.0
    nats:
      image:
        repository: nats-streaming
        tag: 0.6.0