How to set a different namespace for child helm charts?

Question

When you install a chart with a child chart that doesn't specify a namespace, Helm will use the one specified on command line via --namespace. Is it possible to override this flag for a specific child chart?

For example if I have chart A which depends on chart B and I specify --namespace foo, I want to be able to customize the resources of chart B to be installed into some other namespace bar instead of foo.

Answer 1

Update 2: Helm 3 added support for multi namespaces https://github.com/helm/helm/issues/2060

Update 1: If a resource template specifies a metadata.namespace, then it will be installed in that namespace. For example, if I have a pod with metadata.namespace: x and I run helm install mychart --namespace y, that pod will be installed in x. I guess you could use regular helm templates with the namespace to parameterize it.

Original answer:

We do not plan on fully supporting multi-namespaced releases until Helm 3.0 https://github.com/kubernetes/helm/issues/2060#issuecomment-306847365

As a workaround, you install for each namespace individually using --skip-dependencies or with dependency conditions

Answer 2

If you already have different charts then you use helmfile to achieve this.

Step 1: create the following folder.

my-awesome-infrastructure/
  helm
  helmfile
  helmfile.yaml

Where helm and helmfile are the binary executables.

Step 2: install the helm diff plugin which is needed used by helmfile.

helm plugin install https://github.com/databus23/helm-diff

Step 3: declare your charts in the helmfile.yaml.

helmBinary: ./helm

repositories:
  - name: ingress-nginx
    url: https://kubernetes.github.io/ingress-nginx
  - name: bitnami
    url: https://charts.bitnami.com/bitnami
releases:
  - name: nginx-ingress
    namespace: nginx-ingress
    createNamespace: true
    chart: ingress-nginx/ingress-nginx
    version: ~4.1.0
  - name: jupyterhub
    namespace: jupyterhub
    createNamespace: true
    chart: bitnami/jupyterhub
    version: ~1.1.12
  - name: metrics-server
    namespace: metrics-server
    createNamespace: true
    chart: bitnami/metrics-server
    version: ~5.11.9

Step 4: run helmfile to deploy all charts.

./helmfile apply

In the above example, you are deploying three separate charts to three separate namespaces. Under the covers, helmfile will run invoke helm install separately and create separate releases.