DCA Online Practice Questions and Answers

Correct Answer: B

Node taints cannot be used to schedule containers to meet the security policy requirements, because node taints are a Kubernetes concept and not a Swarm concept. According to the official documentation, node taints are used to mark nodes with certain attributes that prevent pods from being scheduled on them unless they have matching tolerations.

Correct Answer: A

This is how they should be distributed across three datacenters or availability zones, because having an even distribution of managers across datacenters or availability zones ensures that the swarm can survive the loss of any one datacenter or availability zone and maintain quorum. According to the official documentation, managers should be distributed evenly across datacenters or availability zones to ensure that the swarm can survive the loss of any one datacenter or availability zone.

Correct Answer: E

Correct Answer: A

Using kubectl describe deployment api displays the events table for this object. The kubectl describe command shows detailed information about a resource, including its status and events. This command can be used to troubleshoot a deployment that is not working as expected

Correct Answer: B

This command will not mount the host's `/data' directory to the ubuntu container in read-only mode, because it has several syntax errors and missing options. According to the official documentation, the correct command should be:

docker run --volume /data:/mydata:ro --read-only ubuntu The errors and missing options are:

The --add-volume flag does not exist and should be replaced by --volume or -v to mount a host directory as a data volume.

The --volume flag requires a colon (:) to separate the host directory and the container directory, not a space.

The --read-only flag applies to the whole container's file system, not just the mounted volume.

To make the volume read-only, a :ro suffix should be added to the --volume flag.

The ubuntu image name should be the last argument of the command.

Correct Answer: B

Using docker inspect http does not enable you to view the list of historical tasks for this service. The docker inspect command shows low-level information about one or more objects, such as containers, images, networks, etc. It does not show information about services or tasks. To view the list of historical tasks for this service, you need to use docker service ps http --no-trunc.

Correct Answer: A

Deleting the image and running garbage collection on the Docker Trusted Registry will completely delete the image from disk. According to the official documentation, this is the recommended way to remove images and reclaim disk space.

Correct Answer: B

Using docker container logs nginx --volumes does not display a list of volumes for a specific container. The docker container logs command shows information about the logs of a container. The --volumes flag is not a valid option for this command and will cause an error. To display a list of volumes for a specific container, you need to use docker container inspect nginx --format `{{ .Mounts }}'.

Correct Answer: B

This strategy does not successfully mount the /data directory on your laptop into a container. Setting containers.mounts.hostBinding to /data in the container's specification is not a valid way to mount a host directory into a container in

Kubernetes. Kubernetes does not support mounting arbitrary host directories into containers, as this would break the portability and isolation of pods across different nodes. To mount a host directory into a container in Kubernetes, you need

to use one of the following methods:

Use hostPath volume, which allows you to mount a file or directory from the host node's filesystem into your pod.

Use local volume, which allows you to mount local storage devices such as disks or partitions into your pod.

Use persistentVolume and persistentVolumeClaim with hostPath or local volume as storage class, which allows you to abstract the details of how storage is provided from how it is consumed.

Correct Answer: B

Setting and exporting the IGNORE_TLS environment variable on the command line is not a way to configure the Docker engine to use a registry without a trusted TLS certificate. The IGNORE_TLS environment variable is not recognized by Docker and has no effect on its behavior. To configure the Docker engine to use a registry without a trusted TLS certificate, you need to either set INSECURE_REGISTRY in the /etc/docker/default configuration file or add --insecure-registry flag to the dockerd command.