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第15章 数据持久化

1.k8s存储介绍​

容器内部的的存储在生命周期是短暂的，会随着容器环境的销毁而销毁，具有不稳定性。在k8s里将对容器应用所需的存储资源抽象为存储卷(Volume)概念来解决这些问题。

k8s目前支持的Volume类型包括k8s的内部资源对象类型，开源共享存储类型和公有云存储等。分类如下：

k8s特定的资源对象：

ConfigMap   应用配置
Secret      加密数据
ServiceAccountToken  token数据

k8s本地存储类型:

EmptDir: 临时存储
HostPath: 宿主机目录

持久化存储(PV)和网络共享存储：

CephFS: 开源共享存储系统
GlusterFS: 开源共享存储系统
NFS:    开源共享存储
PersistentVolumeClaim: 简称PVC，持久化存储的申请空间

2.EmptyDir类型​

cat > emptyDir.yaml << EOF
apiVersion: v1
kind: Pod
metadata:
  name: busybox-empty
spec:
  containers:
  - name: busybox-pod
    image: busybox
    volumeMounts:
    - mountPath: /data/busybox/
      name: cache-volume
    command: ["/bin/sh","-c","while true;do echo $(date) >> /data/busybox/index.html;sleep 3;done"]
  volumes:
  - name: cache-volume
    emptyDir: {}
EOF

3.hostPath类型​

3.1 type类型说明​

https://kubernetes.io/docs/concepts/storage/volumes/#hostpath

DirectoryOrCreate  目录不存在就自动创建
Directory          目录必须存在
FileOrCreate       文件不存在则创建
File               文件必须存在

3.2 创建hostPath类型volume资源配置清单​

apiVersion: v1
kind: Pod
metadata:
  name: busybox-nodename
spec:
  nodeName: node2
  volumes:
  - name: hostpath-volume
    hostPath:
      path: /data/node/
      type: DirectoryOrCreate
  containers:
  - name: busybox-pod
    image: busybox
    volumeMounts:
    - mountPath: /data/pod/
      name: hostpath-volume
    command: ["/bin/sh","-c","while true;do echo $(date) >> /data/pod/index.html;sleep 3;done"]

4.NFS类型​

4.1 NFS类型说明​

我们也可以直接使用Node节点自己本身的nfs软件将共享目录挂载到Pod里，前提是NFS服务已经安装配置好，并且Node节点上安装了NFS客户端软件。

4.2 创建NFS服务​

yum install nfs-utils -y
cat > /etc/exports << 'EOF'
/data/nfs-volume/blog *(rw,sync,no_root_squash)
EOF
mkdir -p /data/nfs-volume/blog
systemctl restart nfs

4.3 创建NFS类型资源清单​

apiVersion: v1
kind: Pod
metadata:
  name: liveness-pod
spec:
  nodeName: node2

  volumes:
  - name: nfs-data
    nfs:
      server: 10.0.0.11
      path: /data/nfs-volume/
  containers:
  - name: liveness
    image: nginx
    imagePullPolicy: IfNotPresent
    ports:
    - name: http
      containerPort: 80
    volumeMounts:
    - name: nfs-data
      mountPath: /usr/share/nginx/html/

5.根据Node标签选择POD创建在指定的Node上​

5.1 方法1: 直接选择Node节点名称​

apiVersion: v1
kind: Pod
metadata:
  name: busybox-nodename
spec:
  nodeName: node2
  containers:
  - name: busybox-pod
    image: busybox
    volumeMounts:
    - mountPath: /data/pod/
      name: hostpath-volume
    command: ["/bin/sh","-c","while true;do echo $(date) >> /data/pod/index.html;sleep 3;done"]
  volumes:
  - name: hostpath-volume
    hostPath:
      path: /data/node/
      type: DirectoryOrCreate

5.2 方法2: 根据Node标签选择Node节点​

节点添加标签

kubectl label nodes node3 disktype=SSD

资源配置清单

apiVersion: v1
kind: Pod
metadata:
  name: busybox-nodename
spec:
  nodeSelector:
    disktype: SSD
  containers:
  - name: busybox-pod
    image: busybox
    volumeMounts:
    - mountPath: /data/pod/
      name: hostpath-volume
    command: ["/bin/sh","-c","while true;do echo $(date) >> /data/pod/index.html;sleep 3;done"]
  volumes:
  - name: hostpath-volume
    hostPath:
      path: /data/node/
      type: DirectoryOrCreate

6.编写mysql的持久化deployment​

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-dp
  namespace: default
spec:
  selector:
    matchLabels:
      app: mysql
  replicas: 1
  template:
    metadata:
      name: mysql-pod
      namespace: default
      labels:
        app: mysql
    spec:
      volumes:
      - name: mysql-volume
        hostPath:
          path: /data/mysql
          type: DirectoryOrCreate
      nodeSelector:
        disktype: SSD
      containers:
      - name: mysql-pod
        image: mysql:5.7
        ports:
        - name: mysql-port
          containerPort: 3306
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "123456"
        volumeMounts:
        - mountPath: /var/lib/mysql
          name: mysql-volume

更新: 2024-09-02 08:57:08

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