Use Helm variables in entrypoint script - kubernetes

Question

I'm struggling to use Helm variables within my entry script for my container, when deploying to AKS. Running locally work perfectly fine, as I'm specifying them as docker -e arguement. How do I pass arguments, either specified as helm variables and/or overwrited when issuing the helm install command?
Entry script start.sh
#!/bin/bash
GH_OWNER=$GH_OWNER
GH_REPOSITORY=$GH_REPOSITORY
GH_TOKEN=$GH_TOKEN
echo "variables"
echo $GH_TOKEN
echo $GH_OWNER
echo $GH_REPOSITORY
echo ${GH_TOKEN}
echo ${GH_OWNER}
echo ${GH_REPOSITORY}
env
Docker file
# base image
FROM ubuntu:20.04
#input GitHub runner version argument
ARG RUNNER_VERSION
ENV DEBIAN_FRONTEND=noninteractive
# update the base packages + add a non-sudo user
RUN apt-get update -y && apt-get upgrade -y && useradd -m docker
# install the packages and dependencies along with jq so we can parse JSON (add additional packages as necessary)
RUN apt-get install -y --no-install-recommends \
curl nodejs wget unzip vim git azure-cli jq build-essential libssl-dev libffi-dev python3 python3-venv python3-dev python3-pip
# cd into the user directory, download and unzip the github actions runner
RUN cd /home/docker && mkdir actions-runner && cd actions-runner \
&& curl -O -L https://github.com/actions/runner/releases/download/v${RUNNER_VERSION}/actions-runner-linux-x64-${RUNNER_VERSION}.tar.gz \
&& tar xzf ./actions-runner-linux-x64-${RUNNER_VERSION}.tar.gz
# install some additional dependencies
RUN chown -R docker ~docker && /home/docker/actions-runner/bin/installdependencies.sh
# add over the start.sh script
ADD scripts/start.sh start.sh
# make the script executable
RUN chmod +x start.sh
# set the user to "docker" so all subsequent commands are run as the docker user
USER docker
# set the entrypoint to the start.sh script
ENTRYPOINT ["/start.sh"]
Helm values
replicaCount: 1
image:
repository: somecreg.azurecr.io/ghrunner
pullPolicy: Always
# tag: latest
imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""
env:
GH_TOKEN: "SET"
GH_OWNER: "SET"
GH_REPOSITORY: "SET"
serviceAccount:
create: true
annotations: {}
name: ""
podAnnotations: {}
podSecurityContext: {}
securityContext: {}
service:
type: ClusterIP
port: 80
ingress:
enabled: false
className: ""
annotations: {}
hosts:
- host: chart-example.local
paths:
- path: /
pathType: ImplementationSpecific
tls: []
resources: {}
autoscaling:
enabled: false
minReplicas: 1
maxReplicas: 100
targetCPUUtilizationPercentage: 80
# targetMemoryUtilizationPercentage: 80
nodeSelector: {}
tolerations: []
affinity: {}
Deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "hostedrunner.fullname" . }}
labels:
{{- include "hostedrunner.labels" . | nindent 4 }}
spec:
{{- if not .Values.autoscaling.enabled }}
replicas: {{ .Values.replicaCount }}
{{- end }}
selector:
matchLabels:
{{- include "hostedrunner.selectorLabels" . | nindent 6 }}
template:
metadata:
{{- with .Values.podAnnotations }}
annotations:
{{- toYaml . | nindent 8 }}
{{- end }}
labels:
{{- include "hostedrunner.selectorLabels" . | nindent 8 }}
spec:
{{- with .Values.imagePullSecrets }}
imagePullSecrets:
{{- toYaml . | nindent 8 }}
{{- end }}
serviceAccountName: {{ include "hostedrunner.serviceAccountName" . }}
securityContext:
{{- toYaml .Values.podSecurityContext | nindent 8 }}
containers:
- name: {{ .Chart.Name }}
securityContext:
{{- toYaml .Values.securityContext | nindent 12 }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
ports:
- name: http
containerPort: 80
protocol: TCP
# livenessProbe:
# httpGet:
# path: /
# port: http
# readinessProbe:
# httpGet:
# path: /
# port: http
resources:
{{- toYaml .Values.resources | nindent 12 }}
{{- with .Values.nodeSelector }}
nodeSelector:
{{- toYaml . | nindent 8 }}
{{- end }}
{{- with .Values.affinity }}
affinity:
{{- toYaml . | nindent 8 }}
{{- end }}
{{- with .Values.tolerations }}
tolerations:
{{- toYaml . | nindent 8 }}
{{- end }}
Console output for helm install
Helm command (tried both with set and set-string and values to get substituted correctly)
helm install --set-string env.GH_TOKEN="$env:pat" --set-string env.GH_OWNER="SomeOwner" --set-string env.GH_REPOSITORY="aks-hostedrunner" $deploymentName .helm/ --debug
I thought the helm variables might be passed as environment variables, but that's not the case. Any input is greatly appreciated

Answer 1

You can add and update your deployment template with
env:
{{- range $key, $val := .Values.env }}
- name: {{ $key }}
value: {{ $val }}
{{- end }}
so it will add the env block into your deployment section and your shell script when will run inside the docker, it will be able to access the Environment variables
Deployment env example
containers:
- name: envar-demo-container
image: <Your Docker image>
env:
- name: DEMO_GREETING
value: "Hello from the environment"
- name: DEMO_FAREWELL
value: "Such a sweet sorrow"
Ref : https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/#define-an-environment-variable-for-a-container
If you will implement above one those variables will get set as Environment variables and Docker will be able to access it(shell script inside the container).
You can also use the configmap and secret of Kubernetes to set values at Env level.