Mirantis Mirantis Certifications DCA Questions & Answers

• Question 41:

  What is used by the kernel to Isolate resources when running Docker containers?

  A. Namespaces

  B. Overlay networks

  C. Volumes

  D. Control groups (also know as cgroups)

  Correct Answer: D

• Question 42:

  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

  Correct Answer: C

• Question 43:

  In the context of a swarm mode cluster, does this describe a node? Solution: an instance of the Docker engine participating in the swarm

  A. Yes

  B. No

  Correct Answer: A

• Question 44:

  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 inspect http'

  A. Yes

  B. No

  Correct Answer: B

  Using `docker service inspect http' does not enable you to view the list of historical tasks for this service. The docker service inspect command shows low-level information about one or more services, such as their configuration, replicas, networks, endpoints, etc. It does not show the history of tasks that have been run by the service. To view the list of historical tasks for this service, you need to use `docker service ps http'.

• Question 45:

  During development of an application meant to be orchestrated by Kubernetes, you want to mount the /data directory on your laptop into a container.

  Will this strategy successfully accomplish this?

  Solution: Create a PersistentVolume with storageciass: "" and hostPath: /data, and a persistentVolumeClaim requesting this PV. Then use that PVC to populate a volume in a pod

  A. Yes

  B. No

  Correct Answer: B

  Creating a PersistentVolume with storageClass: "" and hostPath: /data, and a persistentVolumeClaim requesting this PV, and then using that PVC to populate a volume in a pod is not a strategy that successfully accomplishes this. A PersistentVolume is an API object that represents a piece of storage in the cluster that has been provisioned by an administrator. A PersistentVolumeClaim is a request for storage by a user. A hostPath PersistentVolume uses a file or directory on the node to emulate network-attached storage. However, this type of volume only works on a single node cluster, and it does not work on Windows nodes. Therefore, it cannot be used to mount the /data directory on your laptop into a container.

• Question 46:

  A company's security policy specifies that development and production containers must run on separate nodes in a given Swarm cluster.

  Can this be used to schedule containers to meet the security policy requirements?

  Solution: label contraints

  A. Yes

  B. No

  Correct Answer: A

  Label constraints can be used to schedule containers to meet the security policy requirements. Label constraints are expressions that match node labels to service labels. Node labels are key-value pairs that can be attached to nodes to identify them by certain characteristics, such as role, environment, region, etc. Service labels are key-value pairs that can be attached to services to specify scheduling preferences or requirements, such as node.role == manager or environment != production. Label constraints can be used with the --constraint flag when creating or updating a service to ensure that the service's containers are scheduled on nodes that match the specified criteria.

• Question 47:

  Which 'docker run' flag lifts cgroup limitations?

  A. 'docker run --isolation'

  B. 'docker run --cap-drop'

  C. 'docker run --privileged'

  D. 'docker run --cpu-period'

  Correct Answer: C

• Question 48:

  You add a new user to the engineering organization in DTR.

  Will this action grant them read/write access to the engineering/api repository?

  Solution: Add them to a team in the engineering organization that has read/write access to the engineering/api repository.

  A. Yes

  B. No

  Correct Answer: A

  This action will grant them read/write access to the engineering/api repository, because adding them to a team in the engineering organization that has read/write access to the engineering/api repository is another way to grant permissions to a user in DTR. According to the official documentation, this is an example of using teams and organizations for managing permissions.

• Question 49:

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

  Solution: Uninstall 'docker-ce' package before installing 'docker-ee' package.

  A. Yes

  B. No

  Correct Answer: A

  Uninstalling `docker-ce' package before installing `docker-ee' package does upgrade Docker Engine CE to Docker Engine EE. Docker Engine CE is the free and open source edition of Docker Engine, while Docker Engine EE is the enterprise-ready edition that includes additional features and support. To upgrade from CE to EE, you need to uninstall the `docker-ce' package and its dependencies, and then install the `docker-ee' package from the Docker repository.

• Question 50:

  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

  Correct Answer: A