Passo anterior: Instalação Kubernetes

$ sudo apt install nfs-kernel-server nfs-common

$ MOUNT_POINT=/nfs
$ DISK_DEVICE=/dev/sdb

$ echo -e "n\np\n1\n\n\nw" | sudo fdisk ${DISK_DEVICE}
 
Bem-vindo ao fdisk (util-linux 2.36.1).
As alterações permanecerão apenas na memória, até que você decida gravá-las.
Tenha cuidado antes de usar o comando de gravação.
 
A unidade não contém uma tabela de partição conhecida.
Criado um novo rótulo de disco DOS com o identificador de disco 0x7e42ac59.
 
Comando (m para ajuda): Tipo da partição
   p   primária (0 primárias, 0 estendidas, 4 livre)
   e   estendida (recipiente para partições lógicas)
Selecione (padrão p): Número da partição (1-4, padrão 1): Primeiro setor (2048-268435455, padrão 2048): Último setor, +/-setores ou +/-tamanho{K,M,G,T,P} (2048-268435455, padrão 268435455):
Criada uma nova partição 1 do tipo "Linux" e de tamanho 128 GiB.
 
Comando (m para ajuda): A tabela de partição foi alterada.
Chamando ioctl() para reler tabela de partição.
Sincronizando discos.

$ sudo mkfs.ext4 ${DISK_DEVICE}1
mke2fs 1.46.2 (28-Feb-2021)
Creating filesystem with 33554176 4k blocks and 8388608 inodes
Filesystem UUID: 348ddaa1-0b59-4def-81bc-2e737460013c
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872
 
Allocating group tables: done
Writing inode tables: done
Creating journal (131072 blocks): done
Writing superblocks and filesystem accounting information: done

$ UUID=`sudo blkid -o export ${DISK_DEVICE}1 | grep UUID | grep -v PARTUUID`
$ sudo mkdir ${MOUNT_POINT}
$ sudo cp -p /etc/fstab{,.dist}
$ echo "${UUID}  ${MOUNT_POINT}    ext4    defaults 1 2" | sudo tee -a /etc/fstab
UUID=348ddaa1-0b59-4def-81bc-2e737460013c  /nfs    ext4    defaults 1 2

$ sudo mount ${MOUNT_POINT}
gean@nfs-kube:~$ df -hT | grep nfs
/dev/sdb1      ext4      126G   24K  120G   1% /nfs

$ sudo mkdir /nfs/kubedata
$ sudo chown nobody:nogroup /nfs/kubedata
$ sudo chmod 0777 /nfs/kubedata

$ echo '/nfs/kubedata 177.75.176.32/27(rw,sync,no_subtree_check)' | sudo tee /etc/exports
/nfs/kubedata 177.75.176.32/27(rw,sync,no_subtree_check)

$ sudo systemctl restart nfs-kernel-server
$ sudo exportfs -s
/nfs/kubedata  177.75.176.32/27(rw,wdelay,root_squash,no_subtree_check,sec=sys,rw,secure,root_squash,no_all_squash)

$ sudo exportfs -arv
exporting 177.75.176.32/27:/nfs/kubedata

$ sudo apt install nfs-common

$ sudo showmount -e 177.75.176.43
Export list for 177.75.176.43:
/nfs/kubedata 177.75.176.32/27

$ git clone https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner.git
Cloning into 'nfs-subdir-external-provisioner'...
remote: Enumerating objects: 7248, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (4/4), done.
remote: Total 7248 (delta 0), reused 1 (delta 0), pack-reused 7244
Receiving objects: 100% (7248/7248), 7.99 MiB | 2.13 MiB/s, done.
Resolving deltas: 100% (3900/3900), done.

$ cd nfs-subdir-external-provisioner/deploy/
$ ls
class.yaml  deployment.yaml  objects  rbac.yaml  test-claim.yaml  test-pod.yaml

$ kubectl create ns nfs-system
namespace/nfs-system created

$ vim rbac.yaml
<ESC>:%s/default/nfs-system/g

$ kubectl apply -f rbac.yaml
serviceaccount/nfs-client-provisioner created
clusterrole.rbac.authorization.k8s.io/nfs-client-provisioner-runner created
clusterrolebinding.rbac.authorization.k8s.io/run-nfs-client-provisioner created
role.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created
rolebinding.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created

$ vim class.yaml
<ESC>:%s/false/true/g

$ kubectl apply -f class.yaml
storageclass.storage.k8s.io/nfs-client created

deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-system
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-client-provisioner
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: k8s-sigs.io/nfs-subdir-external-provisioner
            - name: NFS_SERVER
              value: 177.75.176.43
            - name: NFS_PATH
              value: /nfs/kubedata
      volumes:
        - name: nfs-client-root
          nfs:
            server: 177.75.176.43
            path: /nfs/kubedata

$ kubectl apply -f deployment.yaml
deployment.apps/nfs-client-provisioner created

$ kubectl get all -n nfs-system
NAME                                          READY   STATUS    RESTARTS   AGE
pod/nfs-client-provisioner-8686cbd686-dbrgn   1/1     Running   0          71s
 
NAME                                     READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nfs-client-provisioner   1/1     1            1           71s
 
NAME                                                DESIRED   CURRENT   READY   AGE
replicaset.apps/nfs-client-provisioner-8686cbd686   1         1         1       71s

$ kubectl describe pod nfs-client-provisioner-8686cbd686-dbrgn -n nfs-system
Name:         nfs-client-provisioner-8686cbd686-dbrgn
Namespace:    nfs-system
Priority:     0
Node:         kube-worker-01.juntotelecom.com.br/177.75.176.41
Start Time:   Thu, 12 May 2022 18:16:25 -0300
Labels:       app=nfs-client-provisioner
              pod-template-hash=8686cbd686
Annotations:  cni.projectcalico.org/containerID: e7c519c1567b8b149a46b8c72060989ea32cc5aa8360f388a1c8bd247d7f892f
              cni.projectcalico.org/podIP: 10.244.101.70/32
              cni.projectcalico.org/podIPs: 10.244.101.70/32,fd00::33:2603:770f:59b3:71c5/128
Status:       Running
IP:           10.244.101.70
IPs:
  IP:           10.244.101.70
  IP:           fd00::33:2603:770f:59b3:71c5
Controlled By:  ReplicaSet/nfs-client-provisioner-8686cbd686
Containers:
  nfs-client-provisioner:
    Container ID:   cri-o://db4e6e624eec0e8250644e2fb2a78ef6a8a6e8a09a866a9509dc94a135c2c1de
    Image:          k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2
    Image ID:       k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner@sha256:374f80dde8bbd498b1083348dd076b8d8d9f9b35386a793f102d5deebe593626
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Thu, 12 May 2022 18:16:43 -0300
    Ready:          True
    Restart Count:  0
    Environment:
      PROVISIONER_NAME:  k8s-sigs.io/nfs-subdir-external-provisioner
      NFS_SERVER:        177.75.176.43
      NFS_PATH:          /nfs/kubedata
    Mounts:
      /persistentvolumes from nfs-client-root (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-mwt8r (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  nfs-client-root:
    Type:      NFS (an NFS mount that lasts the lifetime of a pod)
    Server:    177.75.176.43
    Path:      /nfs/kubedata
    ReadOnly:  false
  kube-api-access-mwt8r:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason     Age    From               Message
  ----    ------     ----   ----               -------
  Normal  Scheduled  2m24s  default-scheduler  Successfully assigned nfs-system/nfs-client-provisioner-8686cbd686-dbrgn to kube-worker-01.juntotelecom.com.br
  Normal  Pulling    2m22s  kubelet            Pulling image "k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2"
  Normal  Pulled     2m6s   kubelet            Successfully pulled image "k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2" in 16.200017039s
  Normal  Created    2m6s   kubelet            Created container nfs-client-provisioner
  Normal  Started    2m6s   kubelet            Started container nfs-client-provisioner

test-claim.yaml

---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: test-claim
spec:
  storageClassName: nfs-client
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi

$ kubectl apply -f test-claim.yaml
persistentvolumeclaim/test-claim created

$ kubectl get pv,pvc
NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                STORAGECLASS   REASON   AGE
persistentvolume/pvc-523aeaea-f637-4ab5-90d4-2b311586a814   1Mi        RWX            Delete           Bound    default/test-claim   nfs-client              24s
 
NAME                               STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/test-claim   Bound    pvc-523aeaea-f637-4ab5-90d4-2b311586a814   1Mi        RWX            nfs-client     24s

test-pod.yaml

---
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
spec:
  containers:
  - name: test-pod
    image: busybox:stable
    command:
      - "/bin/sh"
    args:
      - "-c"
      - "touch /mnt/SUCCESS && exit 0 || exit 1"
    volumeMounts:
      - name: nfs-pvc
        mountPath: "/mnt"
  restartPolicy: "Never"
  volumes:
    - name: nfs-pvc
      persistentVolumeClaim:
        claimName: test-claim

$ kubectl apply -f test-pod.yaml
pod/test-pod created

No servidor NFS:

$ ls /nfs/kubedata/default-test-claim-pvc-523aeaea-f637-4ab5-90d4-2b311586a814/SUCCESS
/nfs/kubedata/default-test-claim-pvc-523aeaea-f637-4ab5-90d4-2b311586a814/SUCCESS

$ kubectl delete -f test-pod.yaml -f test-claim.yaml
pod "test-pod" deleted
persistentvolumeclaim "test-claim" deleted