[k8s]pod持久存储的几种方式图解

参考: https://kubernetes.io/docs/concepts/storage/volumes/

1.emptyDir

apiVersion: v1
kind: Pod
metadata:
name: test-pd
spec:
containers:
- image: gcr.io/google_containers/test-webserver
name: test-container
volumeMounts:
- mountPath: /cache
name: cache-volume
volumes:
- name: cache-volume
emptyDir: {}

2.hostPath

apiVersion: v1
kind: Pod
metadata:
name: test-pd
spec:
containers:
- image: gcr.io/google_containers/test-webserver
name: test-container
volumeMounts:
- mountPath: /test-pd
name: test-volume
volumes:
- name: test-volume
hostPath:
# directory location on host
path: /data

3.pod持久存储

方式1: pod直接挂载nfs-server

volumes:
- name: nfs
nfs:
server: 192.168.1.1
path:"/"

静态提供：管理员手动创建多个PV，供PVC使用。

动态提供：动态创建PVC特定的PV，并绑定。

方式2: 手动创建pv

pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv003
spec:
capacity:
storage: 5Gi
accessModes:
- ReadWriteOnce
nfs:
path: /somepath
server: 192.168.1.1

$ kubectl get pv
NAME                                       CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS    CLAIM                             STORAGECLASS     REASON    AGE
nfs-pv-heketi                              300Mi      ROX           Retain          Bound     default/nfs-pvc-heketi                                       7d
pvc-02b8a30d-8e28-11e7-a07a-025622f1d9fa   50Gi       RWX           Retain          Bound     kube-public/jenkins-pvc           heketi-storage             5d

pv可以设置三种回收策略：保留（Retain），回收（Recycle）和删除（Delete）。

保留策略：允许人工处理保留的数据。

删除策略：将删除pv和外部关联的存储资源，需要插件支持。

回收策略：将执行清除操作，之后可以被新的pvc使用，需要插件支持。

pv的状态:

Available – 资源尚未被claim使用

Bound – 已经绑定到某个pvc上

Released – 对应的pvc被删除,但是资源还没有被集群回收

Failed – 自动回收失败

访问权限

ReadWriteOnce – 被单个节点mount为读写rw模式

ReadOnlyMany – 被多个节点mount为只读ro模式

ReadWriteMany – 被多个节点mount为读写rw模式

参考: http://dockone.io/article/2290
4000
没什么卵用

pvc.yaml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: myclaim
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi

mypod.yaml

volumes:
- name: mypod
persistentVolumeClaim:
claimName: myclaim

方式3: 自动创建pv–statefulset

参考: https://kubernetes.io/docs/concepts/storage/persistent-volumes/

逻辑关系图解1



逻辑关系图解2



为了说明一个class对应多个pvc.

$ kubectl get pvc
NAME             STATUS    VOLUME          CAPACITY   ACCESSMODES   STORAGECLASS   AGE
nfs-nginx        Bound     nfs-xx          300Mi      ROX                          7d

$ kubectl get pv
NAME                                       CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS    CLAIM                             STORAGECLASS     REASON    AGE
nfs-pv-heketi                              300Mi      ROX           Retain          Bound     default/nfs-pvc-heketi                                       7d
pvc-02b8a30d-8e28-11e7-a07a-025622f1d9fa   50Gi       RWX           Retain          Bound     kube-public/jenkins-pvc           heketi-storage             5d
pvc-05bbb05c-8edf-11e7-a07a-025622f1d9fa   30Gi       RWX           Retain          Bound     kube-public/mysql-develop-pvc     heketi-storage             5d
pvc-0b3ecd56-8ffb-11e7-a07a-025622f1d9fa   50Gi       RWX           Retain          Bound     kube-public/gitlab-pvc            heketi-storage             3d
pvc-4e657ad5-9205-11e7-a07a-025622f1d9fa   2Gi        RWX           Delete          Bound     kube-public/private-pvc           heketi-storage             1d
pvc-73dec4f4-8feb-11e7-a07a-025622f1d9fa   10Gi       RWX           Retain          Bound     kube-public/gitlab-postgres-pvc   heketi-storage             3d
pvc-d74aff4a-91fc-11e7-a07a-025622f1d9fa   2Gi        RWX           Delete          Bound     kube-public/spring-pvc            heketi-storage             1d
pvc-db821d79-8fb6-11e7-a07a-025622f1d9fa   3Gi        RWX           Retain          Bound     kube-public/gitlab-redis-pvc      heketi-storage             3d

参考nfs更能看清晰一些

代码配置逻辑关系图解

实例