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ConfigMaps

A ConfigMap stores non-confidential configuration data as key-value pairs.

  • Decouples configuration from container images
  • Can be consumed as environment variables, command-line arguments, or configuration files mounted in a volume
  • Maximum size: 1 MiB
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Creating a ConfigMap​

From literal values​

kubectl create configmap my-config --from-literal=APP_ENV=production --from-literal=LOG_LEVEL=info

From a file​

kubectl create configmap my-config --from-file=config.yaml

From a manifest​

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  APP_ENV: "production"
  LOG_LEVEL: "info"
  config.yaml: |
    server:
      port: 8080
      timeout: 30s

Using as Environment Variables​

spec:
  containers:
  - name: app
    image: my-app:latest
    envFrom:
    - configMapRef:
        name: my-config

Or individual keys:

env:
- name: APP_ENV
  valueFrom:
    configMapKeyRef:
      name: my-config
      key: APP_ENV

Using as a Volume​

spec:
  containers:
  - name: app
    image: my-app:latest
    volumeMounts:
    - name: config-volume
      mountPath: /etc/config
  volumes:
  - name: config-volume
    configMap:
      name: my-config
  • Each key in the ConfigMap becomes a file in the mounted directory
  • Files are updated automatically when the ConfigMap changes (with a delay)
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