How to pass dynamic arguments to a helm chart that runs a job

Question

I'd like to allow our developers to pass dynamic arguments to a helm template (Kubernetes job). Currently my arguments in the helm template are somewhat static (apart from certain values) and look like this

      Args:
        --arg1
        value1
        --arg2
        value2
        --sql-cmd
        select * from db

If I were run a task using the docker container without Kubernetes, I would pass parameters like so:

docker run my-image --arg1 value1 --arg2 value2 --sql-cmd "select * from db"

Is there any way to templatize arguments in a helm chart in such way that any number of arguments could be passed to a template.

For example.

cat values.yaml
...
arguments: --arg1 value1 --arg2 value2 --sql-cmd "select * from db"
...

or

cat values.yaml
...
arguments: --arg3 value3
...

I've tried a few approaches but was not successful. Here is one example:

     Args:          
      {{  range .Values.arguments }}
        {{ . }}
      {{ end }}

Myron

Answer 1

Yes. In values.yaml you need to give it an array instead of a space delimited string.

cat values.yaml
...
arguments: ['--arg3', 'value3', '--arg2', 'value2']
...

or

cat values.yaml
...
arguments:
- --arg3
- value3
- --arg2
- value2
...

and then you like you mentioned in the template should do it:

     args:          
      {{  range .Values.arguments }}
        - {{ . }}
      {{ end }}

If you want to override the arguments on the command line you can pass an array with --set like this:

--set arguments={--arg1, value1, --arg2, value2, --arg3, value3, ....}

Gillard

How does this work if you call helm install with --set? Can you now set an arbitrary number of arguments with arbitrary names? – Muimuir

If you do --set it basically overrides what's in the values.yaml – Gillard

So you can do --set arg1=val1 --set arg2=val2 etc? – Muimuir

In this case arguments is an array so it would have to be passed like this: `--set arguments={--arg1, value1, --arg2, value2, --arg3, value3, ....}. Passing arrays: github.com/helm/helm/issues/1987 – Gillard

Answer 2

In your values file define arguments as:

extraArgs:
  argument1: value1
  argument2: value2
  booleanArg1:

In your template do:

    args:
{{- range $key, $value := .Values.extraArgs }}
    {{- if $value }}
    - --{{ $key }}={{ $value }}
    {{- else }}
    - --{{ $key }}
    {{- end }}
{{- end }}

Microwave

Answer 3

The arguments format needs to be kept consistent in such cases. Here is my case and it works fine.

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.app.name }}
  labels:
    app: {{ .Values.app.name }}
    instance: test
spec:
  replicas: {{ .Values.master.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Values.app.name }}
      instance: test
  template:
    metadata:
      labels:
        app: {{ .Values.app.name }}
        instance: test
    spec:
      imagePullSecrets:
        - name: gcr-pull-secret
      containers:
        - name: {{ .Values.app.name }}
          image: {{ .Values.app.image }}
          env:
            - name: POD_IP
              valueFrom:
                fieldRef:
                  fieldPath: status.podIP
          args:
              [
               "--users={{int .Values.cmd.users}}",
               "--spawn-rate={{int .Values.cmd.rate}}",
               "--host={{.Values.cmd.host}}",
               "--logfile={{.Values.cmd.logfile}}",
               "--{{.Values.cmd.role}}"]
          ports:
            - containerPort: {{ .Values.container.port }}
          resources:
            requests:
              memory: {{ .Values.container.requests.memory }}
              cpu: {{ .Values.container.requests.cpu }}
            limits:
              memory: {{ .Values.container.limits.memory }}
              cpu: {{ .Values.container.limits.cpu }}

Unfortunately following mixed args format does not work within container construct -

mycommand -ArgA valA --ArgB valB --ArgBool1 -ArgBool2 --ArgC=valC

The correct format of above command expected is -

mycommand --ArgA=valA --ArgB=valB --ArgC=valC --ArgBool1 --ArgBool2

This can be achieved by following constructs -

#Dockerfile last line 
ENTRYPOINT [mycommand]

#deployment.yaml
containers:
  - name: {{ .Values.app.name }}
    image: {{ .Values.app.image }}
    args: [
      "--ArgA={{ .Values.cmd.ArgA }}",
      "--ArgB={{ .Values.cmd.ArgB }}",
      "--ArgC={{ .Values.cmd.ArgC }}",
      "--{{ .Values.cmd.ArgBool1 }}",
      "--{{ .Values.cmd.ArgBool2 }}" ]

#values.yaml
cmd:
   ArgA: valA
   ArgB: valB
   ArgC: valC
   ArgBool1: "ArgBool1"
   ArgBool2: "ArgBool2"

Westwardly

Answer 4

Rico's answer needed to be improved. Using the previous example I've received errors like:

templates/deployment.yaml: error converting YAML to JSON: yaml or

failed to get versionedObject: unable to convert unstructured object to apps/v1beta2, Kind=Deployment: cannot restore slice from string

This is my working setup with coma in elements: ( the vertical format for the list is more readable )

cat values.yaml
...
arguments: [
    "--arg3,", 
    "value3,",
    "--arg2,",
    "value2,",
]
...

in the template should do it:

          args: [
{{  range .Values.arguments }}
{{ . }}
{{ end }}
          ]

Optimum

Which helm chart are you using? – Lindalindahl

@Pau Campaña Soler v2.10.0 – Optimum

Not which version, I mean which helm chart. Jenkins, mongo or whatever. – Lindalindahl

I've used this for my custom microservice, but I think it isn't related to question – Optimum

Answer 5

because of some limitations, I had to work with split and to use a delimiter, so in my case:

deployment.yaml :

        {{- if .Values.deployment.args }}
        args:
        {{- range (split " " .Values.deployment.args) }}
        - {{ . }}
        {{- end }}
        {{- end }}

when use --set:

helm install --set deployment.args="--inspect server.js" ...

results with:

  - args:
    - --inspect
    - server.js

Provencher

Answer 6

helm install --name "airflow" stable/airflow --set secrets.database=mydatabase,secrets.password=mypassword

So this is the helm chart in question: https://github.com/helm/charts/tree/master/stable/airflow Now I want to overwrite the default values in the helm chart secrets.database and secrets.password so I use --set argument and then it is key=value pairs separated by commas.
helm install --name "<name for your chart>" <chart> --set key0=value0,key1=value1,key2=value2,key3=value3

Correggio

Answer 7

Did you try this?

{{  range .Values.arguments }}
{{ . | quote }}
{{ end }}

Allx

Answer 8

Acid R's key/value solution was the only thing that worked for me.

I ended up with this:

values.yaml

arguments: 
  url1: 'http://something1.example.com'
  url2: 'http://something2.example.com'
  url3: 'http://something3.example.com'
  url4: 'http://something3.example.com'

And in my template:

          args: 
          {{- range $key, $value := .Values.arguments }}
            - --url={{ $value }}
          {{- end }}

Podvin

Answer 9

I am using the following schema:

args:
{{- range .Values.deployment.args }}
          - {{ . }}
{{- end }}

.values

deployment:
  args:
    - "a"
    - "--b"
    - "--c"
    - "--verbose"

result exsemple:

  args:
  - a
  - --b
  - --c
  - --verbose

it will be identical:

args: ["a", "--b", "--c", "--verbose"]

Sympetalous

Thank you for your interest in contributing to the Stack Overflow community. This question already has a few answers—including one that has been validated by the community. Are you certain your approach hasn’t been given previously? If so, it would be useful to explain how your approach is different, under what circumstances your approach might be preferred, and/or why you think the previous answers aren’t sufficient. Can you kindly edit your answer to offer an explanation? – Gujarat