Fluentd 在 Kubernetes 下收集日志不可读等问题

Fluentd 在 Kubernetes 下部署时，需要使用 fluentd-daemonset-elasticsearch-rbac.yaml 文件，里面配置了 RABC 权限等，但是启动起来后，查看 Fluentd 日志，发现 unread ，原因是日志位置的问题。

原版日志收集配置：

        volumeMounts:
        - name: varlog
          mountPath: /var/log
        # When actual pod logs in /var/lib/docker/containers, the following lines should be used.
        # - name: dockercontainerlogdirectory
        #   mountPath: /var/lib/docker/containers
        #   readOnly: true
        # When actual pod logs in /var/log/pods, the following lines should be used.
        - name: dockercontainerlogdirectory
          mountPath: /var/log/pods
          readOnly: true
      terminationGracePeriodSeconds: 30
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      # When actual pod logs in /var/lib/docker/containers, the following lines should be used.
      # - name: dockercontainerlogdirectory
      #   hostPath:
      #     path: /var/lib/docker/containers
      # When actual pod logs in /var/log/pods, the following lines should be used.
      - name: dockercontainerlogdirectory
        hostPath:
          path: /var/log/pods

其中，/var/log 部分是不可变化的，有问题的是 dockercontainerlogdirectory 部分。

需要改成：

        volumeMounts:
        - name: varlog
          mountPath: /var/log
        # When actual pod logs in /var/lib/docker/containers, the following lines should be used.
        - name: dockercontainerlogdirectory
          mountPath: /var/lib/docker/containers
          readOnly: true
        # When actual pod logs in /var/log/pods, the following lines should be used.
        # - name: dockercontainerlogdirectory
        #   mountPath: /var/log/pods
        #   readOnly: true
      terminationGracePeriodSeconds: 30
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      # When actual pod logs in /var/lib/docker/containers, the following lines should be used.
      - name: dockercontainerlogdirectory
        hostPath:
          path: /var/lib/docker/containers
      # When actual pod logs in /var/log/pods, the following lines should be used.
      # - name: dockercontainerlogdirectory
      #   hostPath:
      #     path: /var/log/pods