🎯 מטרת התרגול

במעבדה זו נחקור לעומק את:

• emptyDir כ־Ephemeral Storage
• הקשר שלו ל־Pod Lifecycle
• ההבדל בין Container Restart לבין Pod Recreation
• הגדרת Volume בשני מקומות שונים
• שימוש ב־medium ו־sizeLimit
• שיתוף Volume בין Containers
• שימוש ב־readOnly

חלק 1 — יצירת סביבת עבודה נקייה

אנחנו מתחילים עם:

✔ תיקייה חדשה

✔ ללא קבצים קיימים

ניצור קובץ חדש:

vi empty-dir-example.yaml

חלק 2 — יצירת Pod והגדרת emptyDir

הדבק:

apiVersion: v1
kind: Pod
metadata:
  name: empty-dir-demo
spec:
  containers:
    - name: empty-dir-writer

      # Instead of using a custom image,
      # we use BusyBox with tag 1.36.1
      image: busybox:1.36.1

      # We do NOT expose any ports
      # This pod does not need networking for this example

      # We override the command so the container stays alive
      # We pass a list of strings:
      # - "sh" to run shell
      # - "-c" to execute a shell command
      # - "sleep 3600" to keep it running
      command: ["sh", "-c", "sleep 3600"]

      volumeMounts:
        - name: temporary-storage

          # IMPORTANT:
          # This name must match the volume name defined below
          # Up until now, names were mostly arbitrary
          # Here the name acts as a reference
          mountPath: /usr/share/temp

          # This is the directory inside the container
          # where the volume data becomes available

  volumes:
    - name: temporary-storage

      # emptyDir creates ephemeral storage
      # It is bound to the Pod lifecycle
      # If the Pod gets deleted,
      # the directory and ALL stored data are deleted

      emptyDir: {}

      # Empty braces mean:
      # - No medium specified
      # - No sizeLimit specified
      # Default medium is node disk
      # In probably 99% of cases, disk storage is used