How does flux pass env variables dynamically to helm charts using terraform

[Dotisandhyarani]

Auto deploying helm charts with Flux.

I have deployed helm charts using flux in EKS cluster and wanted to pass the env variables to helm charts from terraform.

I have some services deployed with terraform (infra repo) and would like to pass some of those values dynamically to helm charts (helm-repo) as env varaibles . And I have envVariables in values.yaml and would like to pass the values to those env variables using terraform dynamically.

I have defined HelmRelease for each helm chart, I can pass values here but don't want to hardcord in the helmrelease.

HelmRelease

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: analytics
  namespace: flux-system
spec:
  install:
    disableWait: true
  upgrade:
    disableWait: true
  interval: 5m
  chart:
    spec:
      chart: ./charts/src/analytics/analytics/
      sourceRef:
        kind: GitRepository
        name: helm-repo
        namespace: flux-system
      interval: 1m
## We can define values overrides inline via spec.values
#  values:
#    autoscaling:
#      minReplicas: 2

[stefanprodan]

From TF create a Secret or ConfigMap a in the flux-system namespace in this format:

apiVersion: v1
kind: Secret
metadata:
  namespace: flux-system
  name: tf-values
stringData:
  values.yaml: |
     someKey: someValue

Then in the HelmRelease use the Secret:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: analytics
  namespace: flux-system
spec:
  valuesFrom:
  - kind: Secret
    name: tf-values

[Dotisandhyarani]

Excellent, that worked! Thanks for the inputs

Created ConfigMap in terraform like below:

resource "kubernetes_config_map" "analytics-api" {
  metadata {
    name = "analytics-api"
    namespace = "flux-system"
  }
  data = {
    "values.yaml" =  <<YAML
envVariables:
  TABLEPREFIX: ${var.resource_prefix}
YAML
  }
}

and in HelmRelease used the configMap name analytics-api in valuesFrom as

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: analytics-tank
  namespace: flux-system
spec:
  install:
    disableWait: true
  upgrade:
    disableWait: true
  interval: 5m
  chart:
    spec:
      chart: ./charts/src/analytics/analytics-api/
      sourceRef:
        kind: GitRepository
        name: helm-repo
        namespace: flux-system
      interval: 1m
  valuesFrom:
    - kind: ConfigMap
      name: analytics-api
      valuesKey: values.yaml

[mattjamesaus]

I’d love to see this called out in the flux documentation, seems like something we could put into a section of how to integrate it into tool chains like terraform etc.. I’d imagine there’s a few folks out there asking the same qn

[spuxx-dev]

Is there another format for declaring the values in the secret? The drawback of the solution @stefanprodan offered is that even the keys will be hidden when encrypting the secret with SOPS. The only remaining key will be "values.yaml". From a documentation standpoint, that doesn't seem ideal.

[Dentrax]

Is there any examples or doc for the "How does flux pass env variables dynamically to helm charts"?

[matheuscscp]

I don't know what "pass env variables" means in this context, please stop using the term "env vars" here. This is how you pass values to Helm:

https://fluxcd.io/flux/components/helm/helmreleases/#values