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Ghulam Nabi
Asked: 2022-08-07T09:54:55+00:00

Multiple deployment files with a single values file

I am new to Helm and I want to create multiple deployments in k8s from a single deployment YAML file. I’ve used a placeholder in the deployment.yaml like

metadata:
  name: job-{{ .Values.app.ujn }}
...
replicas: {{ .Values.app.replicas }}

and my values.yaml looks like

app:
  replicas: 10
  ujn: 1
---
app:
  replicas: 20
  ujn: 2
---
app:
  replicas: 30
  ujn: 3

The use case is something like that I want to create many deployment files with similar configuration but some params changed and I also don’t want to make multiple values file for each deployment. Can I do something like that in the above example and create multiple files from a single values.yaml?

Also a follow up question, if I deploy this chart on the cluster and if I modify the number of deployments in next deploy, will helm delete the old ones or do those have to be deleted manually?

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1 Answer

  1. The syntax you have puts multiple YAML documents into a single file. It’s unusual for tools to support this well (though kubectl apply and the output of Helm templates do support it); the most common case is that a toll will only read the first document.

    Instead of having multiple documents, you can put a YAML list into the values file.

    # values.yaml
apps:
  - name: '1'
    replicas: 10
  - name: '2'
    replicas: 20
  - name: '3'
    replicas: 30

    Then in your template file, you can use a range loop to loop over this. Here Helm does support multiple documents in a single output stream, so you need to make sure each template begins with the YAML start-of-document marker. Also remember that the range loop rebinds . so you may need different syntax for the top-level Helm objects like .Values or .Release, or if you call a helper template.

    {{- range $app := .Values.apps -}}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ $.Release.Name }}-job-{{ $app.name }}
  # labels: {{- include "mychart.labels" $ | nindent 4 }}
spec:
  replicas: {{ $app.replicas }}
  template: { ... }
{{ end }}
    • 0

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