volume是k8s数据卷，常见的数据卷有4种类型，即EmptyDir，HostDir，NFS，Secret

EmptyDir

EmptyDir是一个空目录，他的生命周期和所属的 Pod 是完全一致的，
可能读者会奇怪，那还要他做什么？EmptyDir的用处是，可以在同一 Pod 内的不同容器之间共享工作过程中产生的文件。
一旦这个pod离开了这个宿主机，EmptyDirr中的数据就会被永久删除


[root@k8s-master demon2]# cat test-emptypath.yaml 
apiVersion: v1
kind: Pod
metadata:
  labels:
    name: test-emptypath
    role: master
  name: test-emptypath
spec:
  containers:
    - name: test-emptypath
      image: registry:5000/back_demon:1.0
      volumeMounts:
       - name: log-storage
         mountPath: /home/laizy/test/
      command:
      - /run.sh
  volumes:
  - name: log-storage
    emptyDir: {}

HostDir

HostDir属性的volume使得对应的容器能够访问当前宿主机上的指定目录。
[root@k8s-master demon2]# cat test-hostpath.yaml 
apiVersion: v1
kind: Pod
metadata:
  labels:
    name: test-hostpath
    role: master
  name: test-hostpath
spec:
  containers:
    - name: test-hostpath
      image: registry:5000/back_demon:1.0
      volumeMounts:
       - name: ssl-certs
         mountPath: /home/laizy/test/cert
         readOnly: true
      command:
      - /run.sh
  volumes:
  - name: ssl-certs
    hostPath:
     path: /etc/ssl/certs

NFS

支持网络存储
[root@k8s-master demon2]# cat test-nfspath.yaml 
apiVersion: v1
kind: Pod
metadata:
  labels:
    name: test-nfspath
    role: master
  name: test-nfspath
spec:
  containers:
    - name: test-nfspath
      image: registry:5000/back_demon:1.0
      volumeMounts:
       - name: nfs-storage
         mountPath: /home/laizy/test/
      command:
      - /run.sh
  volumes:
  - name: nfs-storage
    nfs:
     server: 192.168.20.47
     path: "/data/disk1"

Secret

Secret:Kubemetes提供了Secret来处理敏感数据


[root@k8s-master demon2]# cat secret.yaml 
apiVersion: v1
kind: Secret
metadata:
 name: mysecret
type: Opaque
data:
 username: emhlbnl1
 password: eWFvZGlkaWFv
[root@k8s-master demon2]# cat test-secret.yaml 
apiVersion: v1
kind: Pod
metadata:
  labels:
    name: test-secret
    role: master
  name: test-secret
spec:
  containers:
    - name: test-secret
      image: registry:5000/back_demon:1.0
      volumeMounts:
       - name: secret
         mountPath: /home/laizy/secret
         readOnly: true
      command:
      - /run.sh
  volumes:
  - name: secret
    secret:
     secretName: mysecret

关于Secret 在我另外一篇有详细说明
//www.greatytc.com/p/3bf692ee092e