DCA Exam Dumps : Docker Certified Associate (DCA) Exam

= A persistentVolumeClaim (PVC) is a request for storage by a user. It is similar to a Pod. Pods consume node resources and PVCs consume PV resources1. A PVC can specify a storage class, which is a way of requesting a certain quality of service for the volume2. If the storage class is empty, it means the PVC does not have any specific storage class requirements and can be bound to any PV that satisfies its size and access mode3. However, if there is no existing PV that matches the PVC’s requirements, the PVC remains unbound until a suitable PV becomes available. This can happen either by manual provisioning by an administrator or by dynamic provisioning using StorageClasses1. References:

Persistent Volumes | Kubernetes

Storage Classes | Kubernetes

Configure a Pod to Use a PersistentVolume for Storage | Kubernetes

= Provisioning a Docker config object for each environment is a way to provision configuration to containers at runtime. Docker configs allow services to adapt their behaviour without the need to rebuild a Docker image. Services can only access configs when explicitly granted by a configs attribute within the services top-level element. As with volumes, configs are mounted as files into a service’s container’s filesystem1. Docker configs are supported on both Linux and Windows services2. References: Docker Documentation, Configs top-level element

 SELinux could be blocking the operation of setting the system time from inside a Docker container. SELinux is a security mechanism that enforces mandatory accesscontrol (MAC) policies on Linux systems. It restricts the actions that processes can perform based on their security contexts, such as user, role, type, and level. By default, SELinux prevents Docker containers from accessing or modifying the host’s system time, as this could pose a security risk or cause inconsistency. To allow Docker containers to set the system time, SELinux needs to be configured with the appropriate permissions or labels, or disabled altogether. However, this is not recommended, as it could compromise the security and stability of the system. References:

Change system date time in Docker containers without impacting host

Change Date Inside a Docker Container

How to Handle Timezones in Docker Containers

5 ways to change time in Docker container

How to set system time dynamically in a Docker container