Mirantis Mirantis Certifications DCA Questions & Answers

• Question 141:

  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

  Correct Answer: B

  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 142:

  Which statement is true?

  A. CMD shell format uses this form ["param", param", "param"]

  B. ENTRYPOINT cannot be used in conjuction with CMD

  C. CMD is used to run the software is the image along with any arguments

  D. ENTRYPOINT cannot be overriden in the "docker container run" command

  Correct Answer: A

• Question 143:

  What is the difference between a resource limit and a resource reservation when scheduling services?

  A. A resource limit and a resource reservation can be used interchangeably.

  B. A resource limit is a soft limit for your service, while a reservation is hard limit and the docker engine will do its best to keep your service at the limit.

  C. A resource limit is used to find a host with adequate resources for scheduling a hard limit for your service, while a reservation is hard limit for your service.

  D. A resource limit is hard limit for your service, while a reservation is used to find a host with adequate resources for scheduling. Correct

  Correct Answer: A

• Question 144:

  A user is having problems running Docker. Which of the following will start Docker in debug mode?

  A. Set the debug key to true in the 'daemon.json' file.

  B. Start the 'dockerd' process manually with the '--logging' flag set to debug

  C. Set the logging key to debug in the 'daemon.json' file.

  D. Start the 'dockerd' process manually with the '--raw-logs' flag set to debug

  Correct Answer: A

• Question 145:

  Which set of commands can identify the publishd port(s) for a container? (Choose 1.)

  A. 'docker port inspect', 'docker container inspect'

  B. 'docker container inspect', docker port'

  C. 'docker info','docker network inspect'

  D. 'docker network inspect','docker port'

  Correct Answer: B

• Question 146:

  The following health check exists in a Dockerfile:

  'HEALTCHECK

  CMD curl --fail http://localhost/health || exit 1

  Which of the following describes its purpose?

  A. Defines the action taken when container health fails, which in this case will kill the container with exit status 1.

  B. Defines the health check endpoint on the localhost interface for external monitoring tools to monitor the health of the docker engine.

  C. Defines the health check endpoint on the local host interface for containers to monitor the health of the docker engine.

  D. Defines the health check for the containerized application so that the application health can be monitored by the Docker engine

  Correct Answer: A

• Question 147:

  In the context of a swarm mode cluster, does this describe a node? Solution: a virtual machine participating in the swarm

  A. Yes

  B. No

  Correct Answer: A

  A virtual machine participating in the swarm is a node in the context of a swarm mode cluster. A node is an instance of the Docker engine participating in the swarm. A node can be either a physical machine or a virtual machine. Nodes are either managers or workers. Managers maintain cluster state and manage cluster tasks. Workers execute tasks assigned by managers.

• Question 148:

  You created a new service named 'http' and discover it is not registering as healthy. Will this command enable you to view the list of historical tasks for this service? Solution: 'docker service ps http'

  A. Yes

  B. No

  Correct Answer: A

  Using `docker service ps http' enables you to view the list of historical tasks for this service. The docker service ps command shows information about tasks associated with one or more services. A task is a slot where a container runs to execute a service's commands. A task can have different states in its lifecycle, such as new, running, complete, failed, etc. The docker service ps command shows all tasks by default, including historical ones.

• Question 149:

  Does this describe the role of Control Groups (cgroups) when used with a Docker container? Solution: user authorization to the Docker API

  A. Yes

  B. No

  Correct Answer: B

  This does not describe the role of Control Groups (cgroups) when used with a Docker container, because user authorization to the Docker API is not related to cgroups. According to the official documentation, cgroups are a Linux kernel feature that limits and isolates the resource usage of a group of processes, such as CPU, memory, disk I/O, network, etc. Docker can use cgroups to share available hardware resources to containers and optionally enforce limits and constraints.

• Question 150:

  You want to provide a configuration file to a container at runtime. Does this set of Kubernetes tools and steps accomplish this?

  Solution: Turn the configuration file into a configMap object and mount it directly into the appropriate pod and container using the .spec.containers.configMounts key.

  A. Yes

  B. No

  Correct Answer: B