container didn't get the environment var from CONTAINERD_XXX

[ActivePeter]

I'm using the k3s with https://github.com/k3s-io/k3s/releases/download/v1.30.0%2Bk3s1/k3s & https://github.com/k3s-io/k3s/releases/download/v1.30.0%2Bk3s1/k3s-airgap-images-amd64.tar.gz.

I found the right configuration of proxy is as follows:

• Allow passing targeted environment variables to containerd #3553

• https://docs.k3s.io/advanced#configuring-an-http-proxy

As description, I just need to export the proxy variables when I install the k3s as following:

PROXY="http://192.168.31.53:7890"
os.environ['HTTP_PROXY']=PROXY
os.environ['HTTPS_PROXY']=PROXY
os.environ['NO_PROXY']="127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
os.environ['CONTAINERD_HTTP_PROXY']=PROXY
os.environ['CONTAINERD_HTTPS_PROXY']=PROXY
os.environ['CONTAINERD_NO_PROXY']="127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"

And the environment vars will be added to /etc/systemd/system/k3s.service.env which can be verified.

However, I started a test daemonset to echo the env in pod (containerd), and I got empty environment var:

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: environment-check-daemonset
spec:
  selector:
    matchLabels:
      app: environment-check
  template:
    metadata:
      labels:
        app: environment-check
    spec:
      containers:
      - name: environment-check-container
        image: alpine:latest
        command: ["/bin/sh", "-c"]
        args:
        - echo "http_proxy=$http_proxy" && echo "HTTP_PROXY=$HTTP_PROXY" && echo "https_proxy=$https_proxy" && echo "HTTPS_PROXY=$HTTPS_PROXY" && echo "no_proxy=$no_proxy" && echo "NO_PROXY=$NO_PROXY" && env

Result:

[brandond]

Those environment variables are exported for the containerd process. That does NOT mean that they are injected into container env vars. Env vars for your containers must be set in the pod spec; there is no way built in to Kubernetes or containerd to inject "default" vars that are set even if not in the pod spec.

You might look at tools like: https://github.com/redhat-cop/podpreset-webhook