K8s 資料掛載 - NFS

NFS 怎麼運作

為什麼要用 NFS

• 客戶可以像訪問本地文件一樣訪問遠端主機上的文件。

• 使用共享應用程序可以降低存放成本，並且無需本地硬碟空間。

• 數據中心化可以減少系統管理開銷。
• 降低 Migration 成本

Ubuntu 官方操作教學

Service - NFS | Ubuntu

Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things.

https://ubuntu.com/server/docs/service-nfs

NFS server 架設

1. 安裝並開啟 nfs-kernel-server

sudo apt install nfs-kernel-server
sudo systemctl start nfs-kernel-server.service

1. 設定 /etc/exports 檔案，設定可以共用給 client 的資料夾

sudo vim /etc/exports

/jpetstore *(rw,async,no_subtree_check,no_root_squash)

• sync / async options control whether changes are gauranteed to be committed to stable storage before replying to requests. async thus gives a performance benefit but risks data loss or corruption. Even though sync is the default, it’s worth setting since exportfs will issue a warning if it’s left unspecified.
• 也就是說選擇 sync 會比較慢、async 會比較快（不用等 commit），到時候做實驗可能可以調整這個變因

• With subtree checking enabled, the NFS server checks to ensure that the requested file or directory is within the exported file system tree, and if not, it denies access.

• no_subtree_checkdisables a security verification that subdirectories a client attempts to mount for an exported filesystem are ones they’re permitted to do so.
• 也就是說如果關掉的話效能會比較快，但是可能有資安疑慮，因為不會對 access 的目錄做檢查

• * 必須改成 client 的 ip

• 其他

1. 創建掛載點的資料夾

sudo mkdir /jpetstore

1. apply 設定

sudo exportfs -a

NFS Client 架設

1. 安裝並開啟 nfs-common

sudo apt install nfs-common

1. 創建資料夾並開始掛載！！

sudo mkdir /mnt/nfs-jpetstore
sudo mount {example.hostname.com}:/jpetstore /mnt/nfs-jpetstore

1. 更改 K8s pvc 設定：hostpath → nfs

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv-volume
  namespace: jpetstore-dev
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 140.119.19.25
    path: /jpetstore
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim 
  namespace: jpetstore-dev
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi