In k8s deployed in the state of application, it would normally require persistent storage of data.
Back-end storage of the following ways:
1. The local storage on the host;
(Restart pod, if the pod is scheduled to other nodes, although the data on the original node is not lost, but the application does not store data through other nodes, so it was not persistent)
2. Based on the way through the local cloud storage service, such as: (NFS, glusterfs, cephfs, awsElasticBlockStore, azureDisk, gcePersistentDisk etc.)
(Specify the URL address and the shared directory to mount the volume in the resource list to persistent storage for data)
3. Based on the storage class, to achieve automatic supply PV;
(Creating storage class, and specify the address shared directory to mount the volume in the resource list to achieve persistent storage)
Here we will introduce PV automatically based on the data supplied to the storage class that implements persistent storage
Network concept official explanation:
https://kubernetes.io/docs/concepts/storage/storage-classes/
project address:
https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client/deploy
Project Architecture:
principle:
1. Create a storage class storage engineers.
2. Cluster administrators maintain storage resources in the cluster.
3. The user or developer to submit requirements (as long as the editor in sts in the resource list in the demand for good volumeClaimTemplates ensure correct list of resources to run) This process does not need to manually create the PVC.
Of course, this figure is drawn, detailed division of labor, but in reality a person to believe that these activities are also countless football. kube, kube Pinyin than just a bitter, but no harm to learn more.
As can be seen from the official website currently we do not support NFS storage class, but we can use NFS to support plug-ins.
NFS plug-in project in Github address of : https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client/deploy
Set up
Setting up an NFS service (under the same network segment with the host k8s cluster)
1 install nfs service: yum -y install NFS-safe locking utils (each node in the cluster should be installed or not supported)
2
3 Start nfs and set to boot from the start: systemctl Start nfs && systemctl enable nfs
4
5 create a shared mount directory: mkdir -pv / Data / Volumes / {V1, V2, V3}
. 6
. 7 edit / etc / exports file, to the shared directory 192. 168.1 . 0 / 24 this segment:
. 8
. 9 VI / etc / Exports
10
. 11 / Data / Volume / V1 192.168 . 1.0 / 24 (RW, the no_root_squash)
12 is / Data / Volume / V2 192.168 . 1.0 / 24(RW, the no_root_squash)
13 is / Data / Volume / V3 192.168 . 1.0 / 24 (RW, the no_root_squash)
14
15 Post: the exportfs - AVR
16
. 17 Exporting 192.168 . 1.0 / 24 : / Data / Volume / V3
18 is Exporting 192.168 . 1.0 / 24 : / Data / Volume / V2
. 19 Exporting 192.168 . 1.0 / 24 : / Data / Volume / V1
20 is
21 is to see: the showmount - E
22 is
23 /data/volume/v3 192.168.1.0/24
24 /data/volume/v2 192.168.1.0/24
25 /data/volume/v1 192.168.1.0/24
2. Deploy the plug-in kubernetes in NFS (project address above)
1 下载项目：for file in class.yaml deployment.yaml rbac.yaml test-claim.yaml ; do wget https://raw.githubusercontent.com/kubernetes-incubator/external-storage/master/nfs-client/deploy/$file ; done
2
3 修改资源清单（红色地方需要修改）：
4
5 vim deployment.yaml
6
7 apiVersion: v1
8 kind: ServiceAccount
9 metadata:
10 name: nfs-client-provisioner
11 ---
12 kind: Deployment
13 apiVersion: extensions/v1beta1
14 metadata:
15 name: nfs-client-provisioner
16 spec:
17 replicas: 1
18 strategy:
19 type: Recreate
20 template:
21 metadata:
22 labels:
23 app: nfs-client-provisioner
24 spec:
25 serviceAccountName: nfs-client-provisioner
26 containers:
27 - name: nfs-client-provisioner
28 image: quay.io/external_storage/nfs-client-provisioner:v2.0.0 ##默认是latest版本
29 volumeMounts:
30 - name: nfs-client-root
31 mountPath: /persistentvolumes
32 env:
33 - name: PROVISIONER_NAME
34 value: fuseim.pri/ifs ##这里的供应者名称必须和class.yaml中的provisioner的名称一致，否则部署不成功
35 - name: NFS_SERVER
36 value: k8s-nfs ##这里写NFS服务器的IP地址或者能解析到的主机名
37 - name: NFS_PATH
38 value: /data/volume/v1 ##这里写NFS服务器中的共享挂载目录（强调：这里的路径必须是目录中最后一层的文件夹，否则部署的应用将无权限创建目录导致Pending）
39 volumes:
40 - name: nfs-client-root
41
42 nfs:
43 server: k8s-nfs ##NFS服务器的IP或可解析到的主机名
44 path: /data/volume/v1 ##NFS服务器中的共享挂载目录（强调：这里的路径必须是目录中最后一层的文件夹，否则部署的应用将无权限创建目录导致Pending）
3.部署
切换到此项目的目录中
1 kubectl apply -f ./
4.查看
查看此NFS插件的pod是否部署成功：
1 kubectl get pods
2
3 NAME READY STATUS RESTARTS AGE
4
5 nfs-client-provisioner-8664fb9f68-57wkf 1/1 Running 0 5m43s
5.测试
部署一个pvc或者声明存储的应用，测试是否自动创建出PV而且自动绑定PVC，
1 例：PVC 2
3 4
5 vim test.yaml
6
7 kind: PersistentVolumeClaim
8 apiVersion: v1
9 metadata:
10 name: test-claim
11 annotations:
12 volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
13 spec:
14 accessModes:
15 - ReadWriteMany
16 resources:
17 requests:
18 storage: 1Mi
19
20 例：StatefulSet方式部署的nginx应用
21
22 vim nginx-demo.yaml
23
24 apiVersion: v1
25 kind: Service
26 metadata:
27 name: nginx
28 labels:
29 app: nginx
30 spec:
31 ports:
32 - port: 80
33 name: web
34 clusterIP: None
35 selector:
36 app: nginx
37 ---
38
39 apiVersion: apps/v1
40 kind: StatefulSet
41 metadata:
42 name: web
43 spec:
44 selector:
45 matchLabels:
46 app: nginx
47 serviceName: "nginx"
48 replicas: 3
49 template:
50 metadata:
51 labels:
52 app: nginx
53 spec:
54 terminationGracePeriodSeconds: 10
55 containers:
56 - name: nginx
57 image: nginx
58 ports:
59 - containerPort: 80
60 name: web
61 volumeMounts:
62 - name: www
63 mountPath: /usr/share/nginx/html
64 volumeClaimTemplates:
65 - metadata:
66 name: www
67 spec:
68 accessModes: [ "ReadWriteOnce" ]
69 storageClassName: "managed-nfs-storage"
70 resources:
71 requests:
72 storage: 1Gi
73
74 部署： 75 kubectl apply -f test.yaml nginx-demo.yaml
76 77 查看pod、svc、pv、pvc状态：
78 79 kubectl get pv
80 NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
81 pvc-5d66051e-9674-11e9-9021-000c29cc70d4 1Mi RWX Delete Bound default/test-claim managed-nfs-storage 7m6s
82 pvc-73235c07-9677-11e9-9021-000c29cc70d4 1Gi RWO Delete Bound default/www-web-1 managed-nfs-storage 6m15s
83 pvc-8a58037f-9677-11e9-9021-000c29cc70d4 1Gi RWO Delete Bound default/www-web-2 managed-nfs-storage 5m36s
84 pvc-ab7fca5a-9676-11e9-9021-000c29cc70d4 1Gi RWO Delete Bound default/www-web-0 managed-nfs-storage 7m6s
85
86 87 kubectl get pvc
88 NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
89 test-claim Bound pvc-5d66051e-9674-11e9-9021-000c29cc70d4 1Mi RWX managed-nfs-storage 28m
90 www-web-0 Bound pvc-ab7fca5a-9676-11e9-9021-000c29cc70d4 1Gi RWO managed-nfs-storage 12m
91 www-web-1 Bound pvc-73235c07-9677-11e9-9021-000c29cc70d4 1Gi RWO managed-nfs-storage 6m32s
92 www-web-2 Bound pvc-8a58037f-9677-11e9-9021-000c29cc70d4 1Gi RWO managed-nfs-storage 5m53s
93
94 kubectl get pods -owide 95 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nfs-client-provisioner-f9776d996-dpk6z 1/1 Running 0 12m 10.244.1.65 k8s-node1 <none> <none>
web-0 1/1 Running 0 16m 10.244.1.66 k8s-node1 <none> <none>
web-1 1/1 Running 0 10m 10.244.2.181 k8s-node2 <none> <none>
web-2 1/1 Running 0 10m 10.244.2.182 k8s-node2 <none> <none>
kubectl get svc
现在查看nfs服务器中的v1目录下：
1 default-www-web-0-pvc-c32f532b-968f-11e9-9021-000c29cc70d4 default-www-web-2-pvc-d3944c4a-968f-11e9-9021-000c29cc70d4
2 default-www-web-1-pvc-ccd2a50b-968f-11e9-9021-000c29cc70d4
上面这些是k8s集群映射的目录，用来和其他存储挂载使用，从创建pod时的日志可以看出：
1 Mounting arguments: --description=Kubernetes transient mount for /var/lib/kubelet/pods/7d7c45bc-968c-11e9-9021-000c29cc70d4/volumes/kubernetes.io~nfs/default-www-web-0-pvc-e6b67079-968b-11e9-9021-000c29cc70d4 --scope -- mount -t nfs k8s-nfs:/data/volume/v2/default-www-web-0-pvc-e6b67079-968b-11e9-9021-000c29cc70d4 /var/lib/kubelet/pods/7d7c45bc-968c-11e9-9021-000c29cc70d4/volumes/kubernetes.io~nfs/default-www-web-0-pvc-e6b67079-968b-11e9-9021-000c29cc70d4
在这些目录中创建默认访问页：
. 1 CD default -www-WEB- 0 -PVC-c32f532b-968f-11e9- 9021 - 000c29cc70d4
2
. 3 echo " <h1 of> the NFS Server </ h1 of> " > index.html
. 4
. 5 used in this case nginx pod curl command to access this
6
7 curl 10.244 . 1.66
8
9 NFS Server
Well, that's all the