Add Blog Post for Envfiles

Author: HirazawaUi

content/en/blog/_posts/2025-09-01-introducing-env-files/index.md

@@ -0,0 +1,78 @@
+---
+layout: blog
+title: "Kubernetes v1.34: Introducing Environment variable files"
+date: 2025-0X-XX
+draft: true
+slug: kubernetes-v1-34-env-files
+author: >
+  HirazawaUi
+---
+
+## EnvFiles: A New Approach to Kubernetes Environment Variables
+Kubernetes typically uses `ConfigMaps` and `Secrets` to set environment variables, 
+which introduces additional API calls and complexity,
+For example, you need to separately manage the Pods of your workloads 
+and their configurations, while ensuring orderly 
+updates for both the configurations and the workload Pods.
+
+Alternatively, you might be using a vendor-supplied container 
+that requires environment variables (such as a license key or a one-time token),
+but you don’t want to hard-code them or mount volumes just to get the job done.
+
+At this point, you can use the env files feature, 
+which is managed by the `EnvFiles` feature gate. 
+Currently in the Alpha stage,
+this functionality allows you to load environment variables directly from a file in an emptyDir volume
+without actually mounting that file into the container.
+It’s a simple yet elegant solution to some surprisingly common problems.
+
+## What’s EnvFiles All About?
+At its core, `EnvFiles` allows you to point your container to a file,
+one generated by an `initContainer`,
+and have Kubernetes parse that file to set your environment variables.
+The file lives in an `emptyDir` volume (a temporary storage space that lasts as long as the pod does),
+Your main container doesn’t need to mount the volume.
+The kubelet will read the file and inject these variables when the container starts.
+
+## How It Works
+Here's a simple example:
+```
+apiVersion: v1
+kind: Pod
+spec:
+  initContainers:
+  - name: generate-config
+    image: busybox
+    command: ['sh', '-c', 'echo "CONFIG_VAR=HELLO" > /config/config.env']
+    volumeMounts:
+    - name: config-volume
+      mountPath: /config
+  containers:
+  - name: app-container
+    image: gcr.io/distroless/static
+    env:
+    - name: CONFIG_VAR
+      valueFrom:
+        fileKeyRef:
+          path: config.env
+          volumeName: config-volume
+          key: CONFIG_VAR
+  volumes:
+  - name: config-volume
+    emptyDir: {}
+```
+
+Using EnvFiles is a breeze. 
+You define your environment variables in the pod spec using the `fileKeyRef` field,
+which tells Kubernetes where to find the file and which key to pull.
+The file itself follows standard .env syntax (think KEY=VALUE),
+and it’s stored in an emptyDir volume. 
+The initContainer mounts the volume to write the file, 
+but the main container doesn’t need to—it just gets the variables handed to it at startup.
+
+## A Word on Security
+One quick heads-up: while `EnvFiles` can handle sensitive data like keys or tokens, 
+it’s not a drop-in replacement for Secrets. 
+The `emptyDir` volumes do not provide the same [security protections as Secrets](https://kubernetes.io/docs/concepts/configuration/secret/#information-security-for-secrets).
+so if security is a top concern, stick with Secrets where possible.
+We’ll make sure the docs call this out clearly.