#我的新年Flag#emptydir存储

常用持久化存储

emptyDir
hostPath
nfs
persistenVolumeClaim
glusterfs
cephfs
configMap
secret

volumes 释疑地址

[root@k8smaster4 ~]# kubectl explain pods.spec.volumes
https://kubernetes.io/docs/concepts/storage/volumes#emptydir

持久化存储配置步骤

1. 定义pod 中的 volume，这个volume指明它需要关联到哪个存储
2. 在容器中要使用volumemounts 挂载对应的存储

emptyDir

emptyDir 类型的Volume是在Pod分配到Node上时创建，Kubernetes 会在Node上
自动分配一个目录。目录初始内容为空，当Pod从Node移除时，emptyDir中的数据会被
永久删除。

实例Yaml

[root@k8smaster4 dir]# cat emptydir.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod-empty
spec:
  containers:
  - name: container-empty
    image: docker.io/library/nginx
    imagePullPolicy: IfNotPresent
    volumeMounts:
    - name: cache-volume
      mountPath: /cache   ### 关联容器目录
  volumes:
  - emptyDir: {}   ### 宿主机生成目录
    name: cache-volume

查看Yaml 结果

[root@k8smaster4 dir]# kubectl describe pod pod-empty

查看emptyDir 位置

* 查看结果Yaml，获取UID
[root@k8smaster4 dir]# kubectl get pods pod-empty -o yaml
apiVersion: v1
kind: Pod
metadata:
  annotations:
    cni.projectcalico.org/podIP: 10.244.187.34/32
    cni.projectcalico.org/podIPs: 10.244.187.34/32
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"pod-empty","namespace":"default"},"spec":{"containers":[{"image":"docker.io/library/nginx","imagePullPolicy":"IfNotPresent","name":"container-empty","volumeMounts":[{"mountPath":"/cache","name":"cache-volume"}]}],"volumes":[{"emptyDir":{},"name":"cache-volume"}]}}
  creationTimestamp: "2023-02-06T15:37:23Z"
  name: pod-empty
  namespace: default
  resourceVersion: "4002708"
  uid: 676a6678-ddf7-4a0b-bdf7-17e2a90dec0b
  
  * 查看Pod调度的Node
  [root@k8smaster4 dir]# kubectl get pods -owide
NAME        READY   STATUS    RESTARTS   AGE   IP              NODE       NOMINATED NODE   READINESS GATES
pod-empty   1/1     Running   0          14m   10.244.187.34   k8snode5   <none>           <none>


* 通过UID，查询调度的Node临时目录emptyDir

  [root@k8snode5 ~]# tree /var/lib/kubelet/pods
├── 676a6678-ddf7-4a0b-bdf7-17e2a90dec0b
│   ├── containers
│   │   └── container-empty
│   │       └── 845127dd
│   ├── etc-hosts
│   ├── plugins
│   │   └── kubernetes.io~empty-dir
│   │       ├── cache-volume
│   │       │   └── ready
│   │       └── wrapped_kube-api-access-2d8j9
│   │           └── ready
│   └── volumes
│       ├── kubernetes.io~empty-dir
│       │   └── cache-volume
│       └── kubernetes.io~projected
│           └── kube-api-access-2d8j9
│               ├── ca.crt -> ..data/ca.crt
│               ├── namespace -> ..data/namespace
│               └── token -> ..data/token

 [root@k8snode5 ~]# tree /var/lib/kubelet/pods/676a6678-ddf7-4a0b-bdf7-17e2a90dec0b

查看宿主机临时目录

[root@k8snode5 ~]# cd /var/lib/kubelet/pods/676a6678-ddf7-4a0b-bdf7-17e2a90dec0b
[root@k8snode5 676a6678-ddf7-4a0b-bdf7-17e2a90dec0b]# ls
containers  etc-hosts  plugins  volumes

[root@k8snode5 kubernetes.io~empty-dir]# ls
cache-volume
[root@k8snode5 kubernetes.io~empty-dir]# pwd
/var/lib/kubelet/pods/676a6678-ddf7-4a0b-bdf7-17e2a90dec0b/volumes/kubernetes.io~empty-dir

查看容器目录

[root@k8smaster4 dir]# kubectl exec -it pod-empty  -c container-empty -- /bin/bash
root@pod-empty:/# cd /cache