Docker DCA Online Practice Questions and Exam Preparation

Docker DCA Online Questions & Answers

• Question 181:

  Are these conditions sufficient for Kubernetes to dynamically provision a persistentVolume, assuming there are no limitations on the amount and type of available external storage? Solution: A default storageClass is specified, and subsequently a persistentVolumeClaim is created.

  A. Yes
  B. No
  A. Yes

  ---

  Explanation/Reference:

  These conditions are sufficient for Kubernetes to dynamically provision a persistentVolume, because a default storageClass provides the information needed to create a persistentVolume that matches the persistentVolumeClaim. According to the official documentation, if no storageClass is specified or requested, then the default one is used.

• Question 182:

  Will this action upgrade Docker Engine CE to Docker Engine EE?

  Solution: Disable the Docker service via `chkconfig' or 'systemctl'.

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  Disabling the Docker service via chkconfig or systemctl does not upgrade Docker Engine CE to Docker Engine EE. Disabling the Docker service only stops and prevents Docker from starting automatically on system boot. It does not change or upgrade the version of Docker Engine installed on the system. To upgrade Docker Engine CE to Docker Engine EE, you need to uninstall Docker Engine CE and install Docker Engine EE following the official instructions for your operating system.

• Question 183:

  Will this Linux kernel facility limit a Docker container's access to host resources, such as CPU or memory? Solution: cgroups

  A. Yes
  B. No
  A. Yes

  ---

  Explanation/Reference:

  Using cgroups does limit a Docker container's access to host resources, such as CPU or memory. Cgroups are a Linux kernel feature that allow grouping and managing processes and their resource consumption. They can be used to limit, account, and isolate the resource usage of a container, such as CPU time, memory, disk I/O, network bandwidth, etc.

• Question 184:

  Will a DTR security scan detect this?

  Solution: licenses for known third party binary components

  A. Yes
  B. No
  B. No

• Question 185:

  Will this command mount the host's '/data' directory to the ubuntu container in read-only mode? Solution: 'docker run -v /data:/mydata --mode readonly ubuntu'

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  This command will not mount the host's `/data' directory to the ubuntu container in read-only mode, because it has an incorrect option for making the volume read-only. According to the official documentation, the correct command should be:

  docker run -v /data:/mydata:ro ubuntu

  The incorrect option is:

  The --mode flag does not exist and should be replaced by a :ro suffix to make the volume read-only.

• Question 186:

  Will this Linux kernel facility limit a Docker container's access to host resources, such as CPU or memory?

  Solution: capabilities

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  Capabilities are not a Linux kernel facility that limit a Docker container's access to host resources, such as CPU or memory. Capabilities are a Linux kernel feature that divide the privileges of the root user into distinct units, called capabilities, which can be independently enabled or disabled for each process. Capabilities allow fine-grained control over the operations that a process can perform on the system, such as binding to a privileged port, changing the system time, loading kernel modules, etc. Docker uses capabilities to restrict the default set of capabilities available to the root user inside a container, following the principle of least privilege. However, capabilities do not affect how much CPU or memory a container can use on the host system.

• Question 187:

  You want to mount external storage to a particular filesystem path in a container in a Kubernetes pod. What is the correct set of objects to use for this?

  A. a volume in the pod specification, populated with a perslstentVolumeClaim bound to a perslstentVolume defined by a storageClass
  B. a storageClass In the pod's specification, populated with a volume which Is bound to a provisioner defined by a persistentVolume
  C. a volume in the pod specification, populated with a storageClass which is bound to a provisioner defined by a perslstentVolume
  D. a perslstentVolume in the pod specification, populated with a persistentVolumeClaim which is bound to a volume defined by a storageClass
  B. a storageClass In the pod's specification, populated with a volume which Is bound to a provisioner defined by a persistentVolume

• Question 188:

  Is this a supported user authentication method for Universal Control Plane? Solution: x.500

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  x.500 is not a supported user authentication method for Universal Control Plane (UCP). x.500 is a series of standards for directory services that define how distributed directory information can be accessed and managed over a network. x.500 is not an external authentication backend that UCP supports. UCP supports LDAP, Active Directory, and SAML as external authentication backends.

• Question 189:

  In Docker Trusted Registry, is this how a user can prevent an image, such as 'nginx:latest', from being overwritten by another user with push access to the repository? Solution: Use the DTR web Ul to make all tags in the repository immutable.

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  This is not how a user can prevent an image from being overwritten by another user with push access to the repository, because making all tags in the repository immutable will also prevent the user from updating their own image tags. According to the official documentation, a better way to prevent an image from being overwritten is to use promotion policies that only allow certain users or teams to push images with specific tags.

• Question 190:

  Will this action upgrade Docker Engine CE to Docker Engine EE? Solution: Delete '/var/lib/docker' directory.

  A. Yes
  B. No
  B. No

  ---

  Explanation/Reference:

  Deleting `/var/lib/docker' directory does not upgrade Docker Engine CE to Docker Engine EE. The `/var/lib/docker' directory is where Docker stores all its data and metadata related to containers, images, volumes, networks, etc. Deleting this directory will remove all your Docker data and configurations from your system, but it will not change your Docker version or edition. To upgrade Docker Engine CE to Docker Engine EE, you need to uninstall `docker-ce' package before installing `docker-ee' package.