CODEWITHSUNDEEP
kubernetesenvironment-variablesopenshiftconfigmap
relief.melone
relief.melone

Reputation: 3322

Use Configmap to set group of environment variables

I am currently working on a project where I need to set a bigger number (approx. 20) of environment variables.

Now these variable should be shared with multiple containers inside of a pod. I am using a Configmap to define the values. Now my problem is this. I have to set every Environment variable seperately and also have to do this for every container which just is pretty ugly and alot of unnecessary code. Basically it's looking something like this

kind: Pod
apiVersion: v1
...
containers:
- name: container1
  image: my-image:latest
  env:
  - name: VAR1
    valueFrom:
      configMapKeyRef:
        name: my-config
        key: my-var1
    ...
- name: container2
  image: some-other-image:stable
  env:
  - name: VAR1
    valueFrom:
      configMapKeyRef:
        name: my-config
        key: my-var1
    ...

What I want is to automatically add all the values from my configMap as and environment variable to the container. My first approach is to mount a configMap as volume and then run a shell script on startup. Similar to this

configMap

kind: ConfigMap
apiVersion: v1
...
data:
  envCat.sh: |
    #!/bin/sh
    export $(grep -v '^#' /etc/pod-config/envVars | xargs)
    cat
  envVars
    MY_VAR1="HELLO WORLD!!"
    MY_VAR2="I AM HERE"

Pod

kind: Pod
apiVersion: v1
...
spec:
  volumes:
  - name: config-volume:
    configMap:
      name: my-config
  containers:
  - name: container1
    image: my-image:latest
    volumeMounts:
    - name: config-volume
      mountPath: /etc/pod-config
    command:
    - /etc/pod-config/envCat.sh

Unfortunately the export command works just fine when I run it manually in the container but running the shell script or running /bin/sh /etc/pod-config/envCat.sh is not working.

Any suggestions to achieve what I want to do?

Upvotes: 3

Views: 3069

Answers (2)

mirekphd
mirekphd

Reputation: 6841

Here are examples augmenting the original answer (upvoted) of using spec.containers[0].envFrom in Pods and other k8s/ocp/okd objects:

# kind: Template
# [..]
# objects:
# - kind: DeploymentConfig
# kind: Deployment
kind: Pod 
apiVersion: v1 
metadata:
  name: my-ubuntu
spec:
  containers:
    - name: my-ubuntu
      image: ubuntu:latest 
      envFrom:
        - configMapRef:
            name: example-configmap

kind: ConfigMap
  apiVersion: v1
  metadata:
    name: example-configmap
    namespace: my-namespace
  data:
    NUM_CPUS: "32"
    API_HOST: "localhost:6379"
    LOGGING_LEVEL: "error"

Upvotes: 0

P Ekambaram
P Ekambaram

Reputation: 17689

You should be using envFrom to load all key:value pairs as environment variables inside the container

Upvotes: 7

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