Docker DCA Online Practice Questions and Exam Preparation

Docker DCA Online Questions & Answers

• Question 41:

  Does this command display all the pods in the cluster that are labeled as 'env: development'? Solution: 'kubectl get pods -I env=development'

  A. Yes
  B. No
  A. Yes

• Question 42:

  You want to create a container that is reachable from its host's network. Does this action accomplish this?

  Solution: Use either EXPOSE or --publish to access the containers on the bridge network

  A. Yes
  B. No
  A. Yes

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  Explanation/Reference:

  Using either EXPOSE or --publish to access the containers on the bridge network makes the container reachable from its host's network. The EXPOSE instruction in the Dockerfile specifies which ports the container listens on at runtime,

  while the --publish option maps a port on the host to a port in the container. Both options allow external access to the container's services. References:

  https://docs.docker.com/engine/reference/builder/#expose, https://docs.docker.com/config/containers/container-networking/

• Question 43:

  Which of the following is true about overlay networks?

  A. Overlay networks are created only on the manager node that you created the overlay networking on
  B. Overlay networks are created on all cluster nodes when you create the overlay network.
  C. Overlay networks are first created on the manager nodes. Then they are created on the worker nodes once a task is scheduled on the specific worker node.
  D. Overlay networks are only created on the manager nodes.
  B. Overlay networks are created on all cluster nodes when you create the overlay network.

• Question 44:

  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
  A. 4 managers of which 2 are healthy

• Question 45:

  Can this set of commands identify the published port(s) for a container?

  Solution: `docker port inspect", docker container inspect"

  A. Yes
  B. No
  B. No

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  Explanation/Reference:

  This set of commands cannot identify the published port(s) for a container. The docker port inspect command does not exist and will cause an error. The docker container inspect command shows low-level information about a container in JSON format, but it does not show the public port(s) that are mapped to a private port inside the container. To identify the published port(s) for a container, you can use docker container inspect and docker port commands.

• Question 46:

  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
  A. Docker binds each exposed container port to a random port on all the host's interface

• Question 47:

  You want to create a container that is reachable from its host's network.

  Does this action accomplish this?

  Solution: Use network connect to access the container on the bridge network.

  A. Yes
  B. No
  A. Yes

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  Explanation/Reference:

  Using network connect to access the container on the bridge network does create a container that is reachable from its host's network. The network connect command connects a running container to another network. By default, Docker creates and connects containers to a bridge network, which is an internal network that isolates containers from each other and from the host. However, you can use network connect to connect a container to another network, such as the host network, which allows the container to share the host's network stack and be reachable from the host's network.

• Question 48:

  Will this command ensure that overlay traffic between service tasks is encrypted? Solution: docker service create --network --secure

  A. Yes
  B. No
  B. No

• Question 49:

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

  A. Yes
  B. No
  A. Yes

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  Explanation/Reference:

  A physical 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 50:

  Is this statement correct?

  Solution: A Dockerfile stores persistent data between deployments of a container

  A. Yes
  B. No
  B. No

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  Explanation/Reference:

  A Dockerfile does not store persistent data between deployments of a container. A Dockerfile is a text document that contains instructions for building an image from a base image and other components. A Dockerfile does not store any data itself; it only defines how an image should be built. Persistent data between deployments of a container can be stored using volumes or bind mounts, which are ways of attaching external storage to containers.