Kubernetes envFrom configmap and secrets

Introduction

We can use env from configmap and secrets in pods of kubernetes. If same env variable exists secrets will override configmaps values.

I am describing below one deployment of helm chart

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: {{ template "test-chart.fullname" . }}
  labels:
    app: {{ template "test-chart.name" . }}
    chart: {{ template "test-chart.chart" . }}
    release: {{ .Release.Name }}
    heritage: {{ .Release.Service }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ template "test-chart.name" . }}
      release: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app: {{ template "test-chart.name" . }}
        release: {{ .Release.Name }}
      annotations:
        checksum/config: {{ include (print $.Template.BasePath "/configmaps.yaml") . | sha256sum }}
        checksum/config: {{ include (print $.Template.BasePath "/secrets.yaml") . | sha256sum }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          command:
            - bash
            - "-c"
          args: 
            - set -x; export TERM=xterm; apt update && apt install -y watch && printenv && exec watch printenv;
          envFrom: 
            - configMapRef: 
                name: {{ .Release.Name }}
            - secretRef: 
                name: {{ .Release.Name }}
          resources:
{{ toYaml .Values.resources | indent 12 }}
    {{- with .Values.nodeSelector }}
      nodeSelector:
{{ toYaml . | indent 8 }}
    {{- end }}
    {{- with .Values.affinity }}
      affinity:
{{ toYaml . | indent 8 }}
    {{- end }}
    {{- with .Values.tolerations }}
      tolerations:
{{ toYaml . | indent 8 }}
    {{- end }}

---
apiVersion: v1
kind: Secret
metadata:
  name: {{ .Release.Name }}
type: Opaque
data:
  name: {{ .Release.Name | b64enc }}
  env: {{ "secrets" | b64enc }}
  last: {{ "lastsecret" | b64enc }}
  
  
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ .Release.Name }}
  labels:
    app: {{ template "test-chart.fullname" . }}
data:
  name: {{ .Release.Name }}
  env: configmap
  last: configlast