在K8S中部署NFS服务器并在K8S集群外使用NFS

背景说明

有这样一个场景，我们需要使用多个NFS Server来做负载均衡，Server中保存的文件只读，所以不用考虑数据同步。
一种可能的实现方式是在物理服务器上安装NFS Server，同时安装负载均衡软件来实现（如LVS等），配置起来比较繁琐。
这里考虑在kubernetes集群部署NFS server三副本，同时安装metallb实现负载均衡。

安装负载均衡器

由于这里使用的是rke2搭建的kubernetes集群，需要编辑/etc/rancher/rke2/config.yaml文件，增加如下配置后，重启rke2

kube-proxy-arg: # 不指定的话，默认是 iptables 模式
  - proxy-mode=ipvs
  - ipvs-strict-arp=true

helm一键安装metallb

helm repo add metallb https://metallb.github.io/metallb
helm install metallb metallb/metallb

创建L2Advertisement，使集群外的服务器也可以访问NFS Server

cat<<EOF | kubectl apply -f -
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: first-pool
spec:
  addresses:
  - 192.168.122.20-192.168.122.24
---
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
  name: example
EOF

在kubernetes集群中部署NFS Server

cat<<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-server
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nfs-server
  template:
    metadata:
      labels:
        app: nfs-server
    spec:
      containers:
      - name: nfs-server
        image: k8s.gcr.io/volume-nfs:0.8
        ports:
        - name: nfs
          containerPort: 2049
        - name: mountd
          containerPort: 20048
        - name: rpcbind
          containerPort: 111
        securityContext:
          privileged: true
        volumeMounts:
        - name: storage
          mountPath: /exports
      volumes:
      - name: storage
        hostPath:
          path: /data/nfs # store all data in "/data/nfs" directory of the node where it is running
          type: DirectoryOrCreate # if the directory does not exist then create it
---
apiVersion: v1
kind: Service
metadata:
  name: nfs-service
spec:
  ports:
  - name: nfs
    port: 2049
  - name: mountd
    port: 20048
  - name: rpcbind
    port: 111
  selector:
    app: nfs-server # must match with the label of NFS pod
  type: LoadBalancer
EOF

使用负载均衡测试nfs记录

# kubectl get svc | grep nfs
nfs-service               LoadBalancer   10.43.223.162   192.168.122.21   2049:31390/TCP,20048:31442/TCP,111:31111/TCP   23h

集群外的客户端挂载nfs

mount.nfs4  -onolock 192.168.122.21:/ /mnt
ll /mnt

参考链接：
https://github.com/appscode/third-party-tools/blob/master/storage/nfs/README.md
https://metallb.universe.tf/installation/
https://www.qiniu.com/qfans/qnso-53419624