使用共享卷作为 EmptyDir 的 MultiContainer 可以工作，但是当使用共享卷作为 hostPath 时不工作

Question

我有一个 K8s 集群，其中有一个主节点和一个工作节点。场景 – 1 我正在同一个 POD 中部署一个简单的 sidecar 容器，其中我已将 emptyDir 定义为共享卷，并且它运行良好。清单文件

apiVersion: apps/v1
kind: Deployment
metadata:
   name: pod-with-sidecar
   namespace: test
spec:
   replicas: 1
   selector:
     matchLabels:
         app: debian-nginx
   template:
      metadata:
        labels:
           app: debian-nginx
      spec:
        containers:
        - name: main-debian
          image: debian
          command: ["/bin/sh"]
          args: ["-c", "while true; do date >> /var/log/index.html; sleep 

2;done"]
          volumeMounts:
          - mountPath: /var/log
            name: shared-log
        - name: sidecar-nginx
          image: nginx
          volumeMounts:
          - mountPath: /usr/share/nginx/index.html
            name: shared-log
        volumes:
         - name: shared-log
           emptyDir: {}

在容器 – 1 中创建文件，内容可用，/car/log/index.html 同样在容器 – 2 中创建文件，内容可用usr/share/nginx/html/index.html

然而，在场景 2 中，我在同一个 POD 中部署了相同的简单 sidecar 容器，其中我将 hosPath 定义为共享卷，但它不起作用。清单文件

apiVersion: apps/v1
kind: Deployment
metadata:
    name: pod-with-sidecar
    namespace: test
spec:
   replicas: 1
   selector:
     matchLabels:
         app: debian
         app: nginx
   template:
     metadata:
       labels:
          app: debian
          app: nginx
     spec:
       containers:
       # Main application container
       - name: main-debian
         image: debian
         command: ["/bin/sh", "-c"]
         args: ["while true; do data >> /var/log/index.html; sleep 2;done"]
         volumeMounts:
         - mountPath: /var/log
           name: shared-vol
       # Sidecar container
       - name: sidecar-nginx
         image: nginx:1.7.9
         ports:
         - containerPort: 80
         volumeMounts:
         - mountPath: /usr/share/nginx/html # nginx-specific mount path
           name: shared-vol
       volumes:
       - name: shared-vol
         hostPath:
           path: /mydata
           type: DirectoryOrCreate

在容器 – 1 中创建了文件，但没有可用的内容/car/log/index.html

testuser@kmasterl:~$ kubectl exec -it pod-with-sidecar-85f88c9d5d-xjcgh -c main-debian -n test -- /bin/bash
root@pod-with-sidecar-85f88c9d5d-xjcgh:/# ls -lrt var/log
total 0
-rw-r--r-- 1 root root 0 Dec 14 21:28 index.html
root@pod-with-sidecar-85f88c9d5d-xjcgh:/# cat /var/log/index.html
root@pod-with-sidecar-85f88c9d5d-xjcgh:/#

同样，在容器-2中创建了文件，但没有可用的内容usr/share/nginx/html/index.html

testuser@kmasterl:~$ kubectl exec -it pod-with-sidecar-85f88c9d5d-xjcgh -c sidecar-nginx -n test -- /bin/bash
root@pod-with-sidecar-85f88c9d5d-xjcgh:/# ls -lrt /usr/share/nginx/html
total 0
-rw-r--r-- 1 root root 0 Dec 14 21:28 index.html
root@pod-with-sidecar-85f88c9d5d-xjcgh:/# cat usr/share/nginx/html/index.html
root@pod-with-sidecar-85f88c9d5d-xjcgh:/#

有人能解释为什么它不工作吗主机路径被定义为共享卷??