Environment Variable

Set environment variables on a function’s PodSpec to control runtime behavior or expose Kubernetes Secrets and ConfigMaps. For example, set GOMAXPROCS to tune a Go function’s runtime, or inject a secret value without hardcoding it. Add an env field to the PodSpec to do either.

Docker doesn’t support changing a container’s configuration after it’s created. To keep behavior consistent across executor types, Fission currently only supports setting environment variables at the Environment level.

Add environment variable

Add an env entry to the fetcher container in the environment spec:

apiVersion: fission.io/v1
kind: Environment
...
spec:
  runtime:
    podspec:
      containers:
      - name: fetcher
        env:
        - name: LOG_LEVEL
          value: info

The container now has the variable set:

$ kubectl exec -it <pod> -c fetcher sh
/ # env
LOG_LEVEL=info

Expose Secret/ConfigMap as environment variable

First, create a ConfigMap called my-configmap:

$ kubectl create configmap my-configmap --from-literal=TEST_KEY="TESTVALUE"

Then reference it from the environment spec’s PodSpec using configMapKeyRef:

apiVersion: fission.io/v1
kind: Environment
...
spec:
  runtime:
    podspec:
      containers:
      - name: fetcher
        env:
          - name: TEST_KEY
            valueFrom:
              configMapKeyRef:
                name: my-configmap
                key: TEST_KEY

The ConfigMap value is now available as an environment variable in the container:

$ kubectl exec -it <pod> -c fetcher sh
/ # env
TEST_KEY=TESTVALUE