Example – Python/Flask deployment with ConfigMap

This example builds on our earlier Python/Flask example. This extension will add a ConfigMap that uses both environment variables and structured files, as well as code updates to consume and use those values.

To start, add a ConfigMap with both top-level values and a deeper configuration. The top values will be exposed as environment variables, and the multiline YAML will be exposed as a file inside the container:

# CONFIGURATION FOR THE FLASK APP
kind: ConfigMap
apiVersion: v1
metadata:
  name: flask-config
data:
  CONFIG_FILE: “/etc/flask-config/feature.flags“
  feature.flags: |
    [features]
    greeting=hello
    debug=true

This ConfigMap is mapped with updates to the Pod specification of the deployment with the envFrom key and as a volume to provide the file mapping:

    spec:
      containers:
      - name: flask
        image: quay.io/kubernetes-for-developers/flask:latest
        ports:
        - containerPort: 5000
        envFrom:
...