K8s || pv && pvc
（PersistentVolume，PV）是集群中的一块存储，可以由管理员事先供应，或者 使用存储类（Storage Class）来动态供应。建议k8s集群内的所有的节点都安装nfs-utils软件，因为节点服务器里创建卷需要支持nfs网络文件系统。注意：pv访问模式需要和pvc访问模式要一致，不然会导致pvc创建不成功，状态是pending。保留：pvc被删除后，pv里任然保留pvc曾经的数据，
·
pv和pvc介绍
持久卷（PersistentVolume，PV）是集群中的一块存储，可以由管理员事先供应，或者 使用存储类（Storage Class）来动态供应。
持久卷申领（PersistentVolumeClaim，PVC）表达的是用户对存储的请求。概念上与 Pod 类似。 Pod 会耗用节点资源，而 PVC 申领会耗用 PV 资源。
pv访问模式有：
ReadWriteOnce
卷可以被一个节点以读写方式挂载。 ReadWriteOnce 访问模式也允许运行在同一节点上的多个 Pod 访问卷。
ReadOnlyMany
卷可以被多个节点以只读方式挂载。
ReadWriteMany
卷可以被多个节点以读写方式挂载。
ReadWriteOncePod
卷可以被单个 Pod 以读写方式挂载。
pv的3种回收策略：
保留：pvc被删除后，pv里任然保留pvc曾经的数据，需要手工去删除
回收：被废弃了，不使用这个策略了
删除： 删除的是什么？ 删除动作会将 PersistentVolume 对象从 Kubernetes 中移除。
配置 Pod 以使用 PersistentVolume 作为存储
1.在master和所有的node节点上新建文件夹/mnt/data，同时在里面新建首页文件index.html
[root@k8smaster ~]# mkdir /mnt/data # ---》master上可以不新建，因为不会启动业务pod
[root@k8snode1 ~]# mkdir /mnt/data
[root@k8snode2 ~]# mkdir /mnt/data
[root@k8smaster data]# sh -c "echo 'Hello from Kubernetes storage' > /mnt/data/index.html"
[root@k8smaster data]# ls
index.html
[root@k8smaster data]# echo "sanchuang feng gao zhang liu shen" >>index.html
[root@k8smaster data]# cat index.html
Hello from Kubernetes storage
sanchuang feng gao zhang liu shen
[root@k8snode1 data]# sh -c "echo 'Hello from Kubernetes storage' > /mnt/data/index.html"
[root@k8snode2 data]# sh -c "echo 'Hello from Kubernetes storage' > /mnt/data/index.html"其他的node服务器都查看
[root@k8snode1 ~]# cd /mnt/data/
[root@k8snode1 data]# ls
index.html
[root@k8snode2 ~]# cd /mnt/data/
[root@k8snode2 data]# ls
index.html2.创建 PersistentVolume，创建pv-volume.yaml文件
[root@k8smaster pv]# cat pv-volume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: task-pv-volume
labels:
type: local
spec:
storageClassName: manual # ---》pvc通过这个存储类型的名字和pv绑定
capacity:
storage: 10Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data" 也可以不自己编辑文件，可以去下载，使用下面的命令
kubectl apply -f https://k8s.io/examples/pods/storage/pv-volume.yaml
创建pv
[root@k8smaster pv]# kubectl apply -f pv-volume.yaml
persistentvolume/task-pv-volume created
[root@k8smaster pv]# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
task-pv-volume 10Gi RWO Retain Available manual 4s3.创建 PersistentVolumeClaim--》pvc
注意：pv访问模式需要和pvc访问模式要一致，不然会导致pvc创建不成功，状态是pending
wget https://k8s.io/examples/pods/storage/pv-claim.yaml --no-check-certificate
[root@k8smaster pv]# cat pv-claim.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: task-pv-claim
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 3Gi
[root@k8smaster pv]# kubectl apply -f pv-claim.yaml
persistentvolumeclaim/task-pv-claim created
[root@k8smaster pv]# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
task-pv-claim Bound task-pv-volume 10Gi RWO manual 4s
www-web-0 Pending my-storage-class 4d12h4.创建 Pod使用pvc
wget https://k8s.io/examples/pods/storage/pv-pod.yaml --no-check-certificate
[root@k8smaster pv]# cat pv-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: task-pv-pod
spec:
volumes:
- name: task-pv-storage
persistentVolumeClaim:
claimName: task-pv-claim
containers:
- name: task-pv-container
image: nginx
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
name: "http-server"
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: task-pv-storage
[root@k8smaster pv]# kubectl apply -f pv-pod.yaml
pod/task-pv-pod created
[root@k8smaster pv]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
mypod 1/1 Running 0 82m 10.244.249.26 k8snode1 <none> <none>
task-pv-pod 1/1 Running 0 2m49s 10.244.185.248 k8snode2 <none> <none>5.验证pod是否使用pv里的数据
[root@k8smaster pv]# curl 10.244.185.248
Hello from Kubernetes storage
sanchuang feng gao zhang liu shen
[root@k8smaster pv]# kubectl exec -it task-pv-pod -- bash
root@task-pv-pod:/# cd /usr/share/nginx/html
root@task-pv-pod:/usr/share/nginx/html# ls
index.html
root@task-pv-pod:/usr/share/nginx/html# cat index.html
Hello from Kubernetes storage
sanchuang feng gao zhang liu shenpv+pvc+nfs的实验
1.搭建好nfs服务器
建议k8s集群内的所有的节点都安装nfs-utils软件，因为节点服务器里创建卷需要支持nfs网络文件系统
[root@k8smaster pv]# yum install nfs-utils -y
[root@k8smaster pv]# service nfs restart
Redirecting to /bin/systemctl restart nfs.service
[root@k8smaster pv]# ps aux |grep nfs
root 106106 0.3 1.3 355420 25912 pts/0 T 00:20 0:00 /usr/bin/python /usr/bin/yum install nfs-utils -y
root 107384 0.0 0.0 0 0 ? S< 00:21 0:00 [nfsd4_callbacks]
root 107390 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107391 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107392 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107393 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107394 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107395 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107396 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107397 0.0 0.0 0 0 ? S 00:21 0:00 [nfsd]
root 107447 0.0 0.0 112824 988 pts/0 S+ 00:21 0:00 grep --color=auto nfs2.设置共享目录
[root@k8smaster pv]# vim /etc/exports
[root@k8smaster pv]# cat /etc/exports
/sc/web 192.168.102.0/24(rw,no_root_squash,sync)3.新建共享目录和index.html网页
[root@k8smaster ~]# mkdir /sc/web -p
[root@k8smaster ~]# cd /sc/web
[root@k8smaster web]# echo "welcome to sanchuang" >>index.html
[root@k8smaster web]# ls
index.html
[root@k8smaster web]# cat index.html
welcome to sanchuang4.刷新nfs或者重新输出共享目录
[root@k8smaster web]# exportfs -a # 输出所有共享目录
[root@k8smaster web]# exportfs -v # 显示输出的共享目录
/sc/web 192.168.102.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,rw,secure,no_root_squash,no_all_squash)
[root@k8smaster web]# exportfs -r # 重新输出所有的共享目录
[root@k8smaster web]# exportfs -v
/sc/web 192.168.102.0/24(sync,wdelay,hide,no_subtree_check,sec=sys,rw,secure,no_root_squash,no_all_squash)
[root@k8smaster web]# service nfs restart # 重启nfs服务
Redirecting to /bin/systemctl restart nfs.service
[root@k8smaster web]# ll -d /sc/web
drwxr-xr-x 2 root root 24 4月 4 00:24 /sc/web关闭nfs服务器上的防火墙服务并且设置开机不启动
[root@k8smaster web]# service firewalld stop
Redirecting to /bin/systemctl stop firewalld.service
[root@k8smaster web]# systemctl disable firewalld
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@k8smaster web]# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination在k8s集群里的任意一个节点服务器上测试能否挂载nfs服务器共享的目录
[root@k8snode1 ~]# mount 192.168.102.136:/sc/web /pv_pvc_nfs
mount.nfs: mount point /pv_pvc_nfs does not exist
您在 /var/spool/mail/root 中有新邮件
[root@k8snode1 ~]# mkdir /pv_pvc_nfs
[root@k8snode1 ~]# mount 192.168.102.136:/sc/web /pv_pvc_nfs
[root@k8snode1 ~]# df -Th|grep nfs
192.168.102.136:/sc/web nfs4 50G 5.8G 45G 12% /pv_pvc_nfs5.创建pv使用nfs服务器上的共享目录
[root@k8smaster pv]# vim nfs-pv.yaml
[root@k8smaster pv]# cat nfs-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: sc-nginx-pv
labels:
type: sc-nginx-pv
spec:
capacity:
storage: 10Gi
accessModes:
- ReadWriteMany
storageClassName: nfs # pv对应的名字
nfs:
path: "/sc/web" # nfs共享的目录
server: 192.168.102.136 # nfs服务器的ip地址
readOnly: false # 访问模式
[root@k8smaster pv]# kubectl apply -f nfs-pv.yaml
persistentvolume/sc-nginx-pv created
[root@k8smaster pv]# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
sc-nginx-pv 10Gi RWX Retain Available nfs 3s
task-pv-volume 10Gi RWO Retain Bound default/task-pv-claim manual 47m6.创建pvc使用pv
[root@k8smaster pv]# vim pvc-nfs.yaml
[root@k8smaster pv]# cat pvc-nfs.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: sc-nginx-pvc
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 1Gi
storageClassName: nfs #使用nfs类型的pv
[root@k8smaster pv]# kubectl apply -f pvc-nfs.yaml
persistentvolumeclaim/sc-nginx-pvc created
[root@k8smaster pv]# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
sc-nginx-pvc Bound sc-nginx-pv 10Gi RWX nfs 71s
task-pv-claim Bound task-pv-volume 10Gi RWO manual 45m
www-web-0 Pending my-storage-class 4d12h7.创建pod使用pvc
[root@k8smaster pv]# vim nginx-deployment.yaml
[root@k8smaster pv]# cat nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
volumes:
- name: sc-pv-storage-nfs
persistentVolumeClaim:
claimName: sc-nginx-pvc
containers:
- name: sc-pv-container-nfs
image: nginx
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
name: "http-server"
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: sc-pv-storage-nfs
[root@k8smaster pv]# kubectl apply -f nginx-deployment.yaml
deployment.apps/nginx-deployment created
[root@k8smaster pv]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-deployment-5fc8c46f96-6rtpt 1/1 Running 0 50s 10.244.249.27 k8snode1 <none> <none>
nginx-deployment-5fc8c46f96-cf6wx 1/1 Running 0 50s 10.244.185.251 k8snode2 <none> <none>
nginx-deployment-5fc8c46f96-prj76 1/1 Running 0 50s 10.244.185.250 k8snode2 <none> <none>8.测试访问
[root@k8snode1 ~]# curl 10.244.249.27
welcome to sanchuang
您在 /var/spool/mail/root 中有新邮件
[root@k8snode1 ~]# curl 10.244.185.251
welcome to sanchuang
[root@k8snode1 ~]# curl 10.244.185.250
welcome to sanchuang修改内容
[root@k8smaster web]# echo "teacher feng nfs pv pvc" >> index.html
[root@k8smaster web]# cat index.html
welcome to sanchuang
teacher feng nfs pv pvc再次访问
[root@k8snode1 ~]# curl 10.244.185.250
welcome to sanchuang
teacher feng nfs pv pvc
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