库伯奈特斯什么时候从卷里取东西，什么时候放进卷？

Question

我看到了以下两种类型的volumeMounts

volumeMounts:
- mountPath: <path>
  name: someName

和

volumeMounts:
- name: someNameHere
  mountPath: <somePathHere>

这两者有什么区别？我们何时将内容放入卷中，何时从卷中获取内容？

例如，在链接中，initContainer更新卷，但是nginx容器从该卷获取数据。类似地，侧字符读取卷。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  selector:
    matchLabels:
      app: myapp-dep
  template:
    metadata:
      labels:
        app: myapp-dep
    spec:
      initContainers:
      - name: ssl-cert-creation
        image: deekshithsn/openssl
        command: ["/bin/sh"]
        args: ["-c","mkdir -p /etc/nginx/ssl;openssl req -newkey rsa:2048 -nodes -keyout /etc/nginx/ssl/nginx.key -x509 -days 365 -out /etc/nginx/ssl/nginx.crt -subj '/C=GB/ST=London/L=London/O=Global Security/OU=IT Department/CN=example.com'"]
        volumeMounts: 
          - name: ssl-cert
            mountPath: /etc/nginx/ssl
      containers:
      - name: myapp-dep
        image: deekshithsn/nginxhttps
        command: ["/home/auto-reload-nginx.sh"]
        ports:
        - containerPort: 443
        - containerPort: 80
        livenessProbe:
            httpGet:
              path: /index.html
              port: 80
            initialDelaySeconds: 30
            timeoutSeconds: 1
        volumeMounts:
          - mountPath: /etc/nginx/ssl
            name: ssl-cert
          - mountPath: /etc/nginx/conf.d
            name: nginx-files
          - mountPath: /var/log/nginx
            name: logs

      - name: sidecar-logs
        image: xueshanf/awscli
        command: ["/bin/sh"]
        args: ["-c","cp /root/scripts/syncs3.sh /root/syncs3.sh;chmod 777 /root/syncs3.sh;while true; do sh /root/syncs3.sh; sleep 10;done"]
        volumeMounts:
          - name: logs
            mountPath: /var/log/nginx
          - name: aws-credentials
            mountPath: /root/.aws/config
            subPath: config
          - name: aws-credentials
            mountPath: /root/scripts/syncs3.sh
            subPath: syncs3.sh
      volumes:
        - name: ssl-cert
          emptyDir: {}
        - name: logs
          emptyDir: {}
        - name: aws-credentials
          configMap:
            name: "aws-config"
        - name: nginx-files
          configMap:
            name: "nginx-config"

  replicas: 2

Answer 1

它们在语义上是一样的。VolumeMounts是一个具有mountPath和name两个键的哈希映射。库伯内特斯对他们的解释没有什么不同。

如果您查看的是json表示，而不是yaml，它可能更清楚(键的顺序并不重要)

{
  "volumeMounts": [
    {
      "mountPath": "<path>",
      "name": "name"
    }
  ]
}

{
  "volumeMounts": [
    {
      "name": "someNameHere",
      "mountPath": "<somePathHere>"
    }
  ]
}

卷挂载指定要安装在容器内指定的文件系统位置上的卷。是否读取或写入该卷完全取决于容器中运行的应用程序。是否可以读写取决于文件权限，就像在任何挂载上一样。

更改是否传播到共享相同挂载的其他容器取决于安装传播设置。默认值是None，在这种情况下，它们不会。

Answer 2

volumeMounts:
- mountPath: <somePathHere>
  name: someNameHere

volumeMounts:
- name: someNameHere
  mountPath: <somePathHere>

第一和第二两者都是相同的，存储在卷someNameHere中的所有内容都被安装到路径somePathHere的Pod中。卷安装在图像中指定的路径上。这意味着卷是用pod路径安装的，现在读/写取决于应用程序。