Mirantis Mirantis Certifications DCA Questions & Answers

• Question 31:

  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

  Correct Answer: A

• Question 32:

  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

  Correct Answer: B

• Question 33:

  Is this a function of UCP?

  Solution: image role-based access control

  A. Yes

  B. No

  Correct Answer: A

  Image role-based access control is a function of UCP. UCP allows you to define granular permissions for users and teams to access images stored in DTR. You can assign different roles to users and teams, such as read-only, read-write, or admin, for each image repository or namespace. This way, you can control who can pull or push images to your registry. References: https://docs.docker.com/ee/ucp/

• Question 34:

  Will this command ensure that overlay traffic between service tasks is encrypted? Solution: docker network create -d overlay -o encrypted=true

  A. Yes

  B. No

  Correct Answer: A

  This command will ensure that overlay traffic between service tasks is encrypted, because it uses the -o encrypted=true option to enable encryption for the overlay network. According to the official documentation, when you enable overlay encryption, Docker creates IPSEC tunnels between all the nodes where tasks are scheduled for services attached to the overlay network. These tunnels also use the AES algorithm in GCM mode and manager nodes automatically rotate the keys every 12 hours.

• Question 35:

  What is the purpose of multi-stage builds?

  A. Better logical separation of Dockerfile instructions for better readability

  B. Optimizing images by copying artifacts selectively from previous stages

  C. Better caching when building Docker images

  D. Faster image builds by allowing parallel execution of Docker builds

  Correct Answer: B

• Question 36:

  The following Docker Compose file is deployed as a stack:

  

  Is this statement correct about this health check definition?

  Solution: Health checks test for app health ten seconds apart. Three failed health checks transition the container into "unhealthy" status.

  A. Yes

  B. No

  Correct Answer: A

  This statement is correct about this health check definition. A health check is a feature that allows Docker to monitor the health status of a container by running a command in the container periodically. A health check has three parameters: test, interval, and retries. The test parameter specifies the command to run to check the health of the container. The interval parameter specifies how often to run the health check. The retries parameter specifies how many consecutive failures of the health check are needed to mark the container as unhealthy. In this case, the health check runs curl -f http://localhost/ || exit 1 every 10 seconds to test for app health. If this command fails three times in a row, the container is marked as unhealthy.

• Question 37:

  A container named "analytics" that stores results in a volume called "data" was created.

  docker run -d --name=analytics -v data:/data app1

  How are the results accessed in "data" with another container called "app2"?

  A. docker run -d --name=reports --volume=data app2

  B. docker run -d --name=reports --volumes-from=analytics app2

  C. docker run -d --name=reports --volume=app1 app2

  D. docker run -d --name=reports --mount=app1 app2

  Correct Answer: B

• Question 38:

  You have just executed 'docker swarm leave' on a node. What command can be run on the same node to confirm it has left the cluster?

  A. docker node ls

  B. docker system info

  C. docker system status

  D. docker system status

  Correct Answer: B

• Question 39:

  Seven managers are in a swarm cluster.

  Is this how should they be distributed across three datacenters or availability zones?

  Solution: 5-1-1

  A. Yes

  B. No

  Correct Answer: B

  This is not how they should be distributed across three datacenters or availability zones, because having one manager in two datacenters or availability zones creates a risk of losing quorum if those datacenters or availability zones become unavailable. 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.

• Question 40:

  Which of the following commands wifi automatically create a volume when a container is started?

  A. 'docker container run --name nginxtest --volumes=/app nginx'

  B. 'docker container run --name nginxtest -v /app:mount nginx'

  C. 'docker container run --name nginxtest --volumes myvol:/app:new nginx'

  D. 'docker container run --name nginxtest -v myvol:/app nginx'

  Correct Answer: A