Docker DCA Free Practice Questions

NEW QUESTION 1
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

Answer: A

NEW QUESTION 2
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

Answer: A

NEW QUESTION 3
Which of the following are types of namespaces used by Docker to provide isolation? (Choose 2.)

• A. Host
• B. Network
• C. Process ID
• D. Authentication
• E. Storage

Answer: BC

NEW QUESTION 4
Which of the following is NOT backed up when performing a Docker Trusted backup operation?

• A. Access control to repos and images
• B. Repository metadata
• C. Image blobs
• D. DTR configurations

Answer: C

NEW QUESTION 5
You have deployed a service to swarm. Which command uses the Docker CLI to set the number of tasks of the services to 5? (choose 2)

• A. 'docker service update --replicas=5 <service-id>'
• B. 'docker replica update <service-id>=5'
• C. 'docker update service <service-id>=5'
• D. 'docker service replicas <service-id>=5'
• E. 'docker service scale <service-id> = 5''

Answer: AE

NEW QUESTION 6
Which of the following is true about using the '-P' option when creating a new container?

• A. Docker binds each exposed container port to a random port on all the host's interface
• B. Docker gives extended privileges to the container.
• C. Docker binds each exposed container port to a random port on a specified host interface
• D. Docker binds each exposed container port with the same port on the host

Answer: AExplanationControllare

NEW QUESTION 7
Which of the following constitutes a production-ready devicemapper configuration for the Docker engine?

• A. Create a volume group in devicemapper and utilize the '--dm.thinpooldev' Docker daemon option, specifying the volume group
• B. Format a partition with xfs and mount it at '/var/lib/docker'
• C. Utilize the '--storage-opt dm.directlvm_device' Docker daemon option, specifying a block device
• D. Nothing, devicemapper comes ready for production usage out of the box

Answer: C

Explanation:
Explanation

NEW QUESTION 8
What behavior is expected when a service is created with the following command: 'docker service create --publish 8000:80 nginx'

• A. All nodes in the cluster will listen on port 8080 and forward to port 80 in the container.
• B. Only a single node in the cluster will listen on port 8080 and forward to port 80 in the container.
• C. All nodes in the cluster will listen on port 80 and forward to port 8080 in the container.
• D. Only a single node in the cluster will listen on port 80 and forward to port 8080 in the container.

Answer: A

NEW QUESTION 9
Which flag for a service would allow a container to consume more than 2 GB of memory only when there is no memory contention but would also prevent a container from consuming more than 4GB of memory, in any case?

• A. --limit-memory 2GB --reserve-memory 4GB
• B. --limit-memory 4GB --reserve-memory 2GB
• C. --memory-swap 2GB --limit-memory 4GB
• D. --memory-swap 4GB --limit-memory 2GB

Answer: C

NEW QUESTION 10
Which statement is true about DTR garbage collection?

• A. Garbage collection removes unreferenced image layers from DTR's backend storage.
• B. Garbage collection removes exited containers from cluster nodes.
• C. Garbage collection removes DTR images that are older than a configurable of days
• D. Garbage collection removes unused volumes from cluster nodes

Answer: A

NEW QUESTION 11
After creating a new service named 'http', you notice that the new service is not registering as healthy. How do you view the list of historical tasks for that service by using the command line?

• A. 'docker inspect http'
• B. 'docker service inspect http'
• C. 'docker service ps http'
• D. 'docker ps http'

Answer: C

NEW QUESTION 12
When seven managers are in a swarm cluster how would they be distributed across three datacenters or availability zones?

• A. 5-1-1
• B. 3-2-2
• C. 3-3-1
• D. 4-2-1

Answer: B

NEW QUESTION 13
Which of the following is required to install Docker EE from a package repository?

• A. Repository URL obtained from Docker Store
• B. License key obtained from Docker Store
• C. Repository URL obtained from Docker Hub
• D. License key obtained from Docker Hub

Answer: A

NEW QUESTION 14
Which command interactively monitors all container activity in the Docker engine?

• A. docker system logs
• B. docker system events
• C. docker container events
• D. docker container logs

Answer: B

NEW QUESTION 15
How do you configure Docker engine to use a registry that is not configured with TLS certificates from a trusted CA?

• A. Set IGNORE_TLS in the 'daemon.json' configuration file.
• B. Set and export the IGNORE_TLS environment variable on the command line
• C. Set INSECURE_REGISTRY in the '/etc/docker/default' configuration file
• D. Pass the '--insecure.-registry' flag to the daemon at run time

Answer: D

NEW QUESTION 16
From a DevOps process standpoint, it is best practice to keep changes to an application in version control. Which of the following will allow changes to a docker Image to be stored in a version control system?

• A. docker commit
• B. docker save
• C. A docker-compose.yml file
• D. A dockerfile

Answer: A

NEW QUESTION 17
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

Answer: A

NEW QUESTION 18
Which of these swarm manager configurations will cause the cluster to be in a lost quorum state?

• A. 4 managers of which 2 are healthy
• B. 1 manager of which 1 is healthy
• C. 3 managers of which 2 are healthy
• D. 5 managers of which 3 are healthy

Answer: A

NEW QUESTION 19
Which of the following namespaces is disabled by default and must be enabled at Docker engine runtime in order to be used?

• A. user
• B. pid
• C. net
• D. mnt

Answer: A

NEW QUESTION 20
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 schedulin
• E. Correct

Answer: A

NEW QUESTION 21
You have created a Docker bridge network on a host with three containers attached, how do you make this containers accessible outside of the host?

• A. Use network attach to access the containers on the bridge network
• B. Use either EXPOSE or --publish to access the containers on the bridge network
• C. Use network connect to access the containers on the bridge network
• D. Use --link to access the containers on the bridge network Correct

Answer: B

NEW QUESTION 22
A host machine has four CPUs available and two running containers. The sysadmin would like to assign two CPUs to each container.
Which of the following commands achieves this?

• A. Set the '--cpuset-cpu's flag to '1.3' on one container and '2.4' on the other container.
• B. Set the '--cpuset-cpus' flag to '.5' on both containers
• C. Set the '--cpuset-cpus' flag of the 'dockerd' process to the value 'even-spread'
• D. Set the '--cpu-quota' flag to '1.3' on one container and '2,4' on the other container.

Answer: B

NEW QUESTION 23
What is the docker command to find the current logging driver for a running container?

• A. docker stats
• B. docker info
• C. docker config
• D. docker inspect

Answer: D

NEW QUESTION 24
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