NEW 2024 Certification Sample Questions DCA Dumps & Practice Exam
DCA Deluxe Study Guide with Online Test Engine
The DCA exam consists of 55 multiple-choice questions, which must be answered within 90 minutes. To pass the exam, candidates must score at least 65%. DCA exam is available in multiple languages, including English, Japanese, and Simplified Chinese. DCA exam can be taken online or at an authorized testing center.
Docker Certified Associate (DCA) certification exam is a globally recognized certification that validates the knowledge and skills of professionals in using Docker Enterprise Edition (EE) and Docker Community Edition (CE) for containerization. Docker Certified Associate (DCA) Exam certification is designed to help IT professionals and developers to showcase their proficiency in Docker technologies and to demonstrate their ability to use Docker to build, ship, and run containerized applications.
NEW QUESTION # 19
Two development teams in your organization use Kubernetes and want to deploy their applications while ensuring that Kubernetes-specific resources, such as secrets, are grouped together for each application.
Is this a way to accomplish this?
Solution: Create one namespace for each application and add all the resources to it.
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Namespaces in Kubernetes are a way to create and organize virtual clusters within physical clusters where we can isolate a group of resources within a single cluster1. Namespace helps to organize resources such as pods, services, and volumes within the cluster2. By creating one namespace for each application and adding all the resources to it, the development teams can ensure that Kubernetes-specific resources, such as secrets, are grouped together for each application. This also provides a scope for names, a mechanism to attach authorization and policy, and a way to divide cluster resources between multiple users3. References:
* Namespaces | Kubernetes
* Kubernetes - Namespaces - GeeksforGeeks
* Namespaces Walkthrough | Kubernetes
NEW QUESTION # 20
Your organization has a centralized logging solution, such as Splunk.
Will this configure a Docker container to export container logs to the logging solution?
Solution: Set the log-driver and log-oPt keys to values for the logging solution (Splunk) In the daemon.json file.
- A. Yes
- B. No
Answer: A
NEW QUESTION # 21
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 constraints
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Label constraints can be used to schedule containers to meet the security policy requirements. Label constraints are a way to specify which nodes a service can run on based on the labels assigned to the nodes.
Labels are key-value pairs that can be attached to any node in the swarm. For example, you can label nodes as development or production depending on their intended use. Then, you can use the --constraint option when creating or updating a service to filter the nodes based on their labels. For example, to run a service only on development nodes, you can use:
docker service create --constraint'node.labels.environment == development'...
To run a service only on production nodes, you can use:
docker service create --constraint'node.labels.environment == production'...
This way, you can ensure that development and production containers run on separate nodes in the swarm, as required by the security policy. References:
* Using placement constraints with Docker Swarm
* Multiple label placement constraints in docker swarm
* Machine constraints in Docker swarm
* How can set service constraint to multiple value
NEW QUESTION # 22
Following the principle of least privilege, which of the following methods can be used to securely grnt access to the specific user to communicate to a Docker engine? (Choose two.)
- A. Utilize the '--host 0.0.0.0:2375' option to the Docker daemon to listen on port 2375 over TCP on all interfaces
- B. Utilize openssl to create TLS client and server certificates, configuring the Docker engine to use with mutual TLS over TCP.
- C. Utilize the '--host 127.0.0.1:2375' option to the Docker daemon to listen on port 2375 over TCP on localhost
- D. Add the user to the 'docker' group on the server or specify the groue with the '--group' Docker daemon option.
- E. Give the user root access to the server to allow them to run Docker commands as root.
Answer: B,D
NEW QUESTION # 23
When using the Docker client to push an image to a registry, what environment variable is used to instruct the client to perform signing of the image?
- A. DOCKER_CONTENT_TRUST=1
- B. DOCKER_PUSH_SIGN=1
- C. DOCKER_IMAGE_SIGN=1
- D. NOTARY_ENABLE=1
Correct
Answer: A
NEW QUESTION # 24
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 # 25
You want to create a container that is reachable from its host's network. Does this action accomplish this?
Solution: Use --link to access the container on the bridge network.
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
Using --link to access the container on the bridge network does not make the container reachable from its host's network. The --link option allows containers to communicate with each other using a private network created by Docker. To make a container reachable from its host's network, you need to use either EXPOSE or
--publish to access the containers on the bridge network. References: https://docs.docker.com/network/links/,
https://docs.docker.com/network/bridge/
NEW QUESTION # 26
Which of the following statements is true about secrets?
- A. Secrets can be created from any node in the cluster.
- B. Secrets can be modified after they are created.
- C. Secret are stored unencrypted on manager nodes.
- D. Secrets can be created using standard input (STDIN) and a file.
Answer: D
NEW QUESTION # 27
Will this command list all nodes in a swarm cluster from the command line?
Solution: 'docker Is -a'
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
The command docker Is -a does not list all nodes in a swarm cluster from the command line, but rather lists all containers, both running and stopped, on the current node1. To list all nodes in a swarm cluster, you need to use the command docker node ls from a manager node2. This command shows the node ID, hostname, status, availability, and manager status for each node in the swarm2. You can also use the --filter option to filter the output based on various criteria2. References: Docker Documentation, docker node ls
NEW QUESTION # 28
Is this a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used?
Solution: user
- A. Yes
- B. No
Answer: A
NEW QUESTION # 29
You configure a local Docker engine to enforce content trust by setting the environment variable DOCKER_CONTENT_TRUST=1.
If myorg/myimage: 1.0 is unsigned, does Docker block this command?
Solution: docker image import <tarball> myorg/myimage:1.0
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Docker Content Trust (DCT) is a feature that allows users to verify the integrity and publisher of container images they pull or deploy from a registry server, signed on a Notary server1. DCT is enabled by setting the environment variable DOCKER_CONTENT_TRUST=1 on the Docker client. When DCT is enabled, the Docker client will only pull, run, or build images that have valid signatures for a specific tag2. However, DCT does not apply to the docker image import command, which allows users to import an image or a tarball with a repository and tag from a file or STDIN3. Therefore, if myorg/myimage:1.0 is unsigned, Docker will not block the docker image import <tarball>myorg/myimage:1.0 command, even if DCT is enabled. This is because the docker image import command does not interact with a registry or a Notary server, and thus does not perform any signature verification. However, this also means that the imported image will not have any trust data associated with it, and it will not be possible to push it to a registry with DCT enabled, unless it is signed with a valid key. References:
* Content trust in Docker
* Automation with content trust
* [docker image import]
* [Content trust and image tags]
NEW QUESTION # 30
Does this describe the role of Control Groups (cgroups) when used with a Docker container?
Solution: accounting and limiting of resources
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
This does describe the role of Control Groups (cgroups) when used with a Docker container, because accounting and limiting of resources is one of the main functions of cgroups. According to the official documentation, cgroups are a Linux kernel feature that limits and isolates the resource usage of a group of processes, such as CPU, memory, disk I/O, network, etc. Docker can use cgroups to share available hardware resources to containers and optionally enforce limits and constraints.
References: https://docs.docker.com/config/containers/runmetrics/
https://bikramat.medium.com/namespace-vs-cgroup-60c832c6b8c8
NEW QUESTION # 31
The output of which command can be used to find the architecture and operating system an image is
compatible with?
- A. docker image info <image-id>
- B. docker image inspect --format {{.Architecture}} {{.OS}} ' <image-id>
- C. docker image ls <image-id>
- D. docker image inspect --filter {{.Architecture}} {{.OS}} ' <image-id>
Answer: B
NEW QUESTION # 32
You want to provide a configuration file to a container at runtime. Does this set of Kubernetes tools and steps accomplish this?
Solution: Mount the configuration file directly into the appropriate pod and container using the
.spec.containers.configMounts key.
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
This set of Kubernetes tools and steps does not accomplish this, because there is no such key as
.spec.containers.configMounts in the pod specification. According to the official documentation, the correct key to use for mounting a configuration file directly into a container is .spec.containers.volumeMounts, which requires a corresponding volume definition in .spec.volumes.
References:
https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/#add-configmap-data-to-a-vo
https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.22/#container-v1-core
NEW QUESTION # 33
Two development teams in your organization use Kubernetes and want to deploy their applications while ensuring that Kubernetes-specific resources, such as secrets, are grouped together for each application.
Is this a way to accomplish this?
Solution: Create one pod and add all the resources needed for each application
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
Creating one pod and adding all the resources needed for each application is not a good way to accomplish the goal of grouping Kubernetes-specific resources for each application. This is because pods are the smallest unit of a Kubernetes application, and they are designed to run a single container or a set of tightly coupled containers that share the same network and storage resources1. Pods are ephemeral and can be created and destroyed by the Kubernetes system at any time. Therefore, putting multiple applications in one pod would make them harder to manage, scale, and update independently. A better way to accomplish the goal is to use namespaces, which are logicalclusters within a physical cluster that can isolate resources, policies, and configurations for different applications2. Namespaces can also help organize secrets, which are Kubernetes objects that store sensitive information such as passwords, tokens, and keys3. References:
* Pods | Kubernetes
* Namespaces | Kubernetes
* Secrets | Kubernetes
NEW QUESTION # 34
You are pulling images from a Docker Trusted Registry installation configured to use self-signed certificates, and this error appears:
'x509: certificate signed by unknown authority'.
You already downloaded the Docker Trusted Registry certificate authority certificate from https://dtr.example.com/ca.
How do you trust it? (Select two.)
- A. Place the certificate in your OS certificate path, trust the certificate system-wide, and restart the Docker daemon across all cluster nodes.
- B. Place the certificate in '/etc/docker/dtr/dtr.example.com.crt' and restart the Docker daemon on all cluster nodes.
- C. Pass --insecure-registry to the Docker client.
- D. Place the certificate in '/etc/docker/certs.d/dtr.example com/ca.crt' on all cluster nodes.
- E. Pass '-trust-certificate ca.crt' to the Docker client.
Answer: C,D
NEW QUESTION # 35
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 a specified host interface
- B. Docker binds each exposed container port with the same port on the host
- C. Docker gives extended privileges to the container.
- D. Docker binds each exposed container port to a random port on all the host's interface
Answer: D
NEW QUESTION # 36
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 ps http'
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Using 'docker service ps http' enables you to view the list of historical tasks for this service. The docker service ps command shows information about tasks associated with one or more services. A task is a slot where a container runs to execute a service's commands. A task can have different states in its lifecycle, such as new, running, complete, failed, etc. The docker service ps command shows all tasks by default, including historical ones. References: https://docs.docker.com/engine/reference/commandline/service_ps/,
https://docs.docker.com/engine/swarm/how-swarm-mode-works/services/
NEW QUESTION # 37
You configure a local Docker engine to enforce content trust by setting the environment variable DOCKER_CONTENT_TRUST=1.
If myorg/myimage: 1.0 is unsigned, does Docker block this command?
Solution: docker service create myorg/myimage:1.0
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
When content trust is enabled, Docker blocks any command that operates on unsigned images, such as docker service create. This is because Docker Content Trust (DCT) allows users to verify the integrity and publisher of specific image tags, using digital signatures stored on a Notary server. If an image tag is not signed, or the signature cannot be verified, Docker will refuse to pull, run, or build with that image. Therefore, if myorg/myimage:1.0 is unsigned, Docker will block the command docker service create myorg/myimage:1.0 and display an error message. References:
* Content trust in Docker
* Docker Content Trust: What It Is and How It Secures Container Images
* Automation with content trust
NEW QUESTION # 38
Will this command display a list of volumes for a specific container?
Solution: docker volume inspect nginx'
- A. No
- B. Yes
Answer: A
NEW QUESTION # 39
Which statement is true about DTR garbage collection?
- A. Garbage collection removes DTR images that are older than a configurable of days
- B. Garbage collection removes unused volumes from cluster nodes
- C. Garbage collection removes unreferenced image layers from DTR's backend storage.
- D. Garbage collection removes exited containers from cluster nodes.
Answer: C
NEW QUESTION # 40
Following the principle of least privilege, which of the following methods can be used to securely grnt access to the specific user to communicate to a Docker engine? (Choose two.)
- A. Add the user to the 'docker' group on the server or specify the grouè with the '--group' Docker daemon option.
- B. Utilize the '--host 127.0.0.1:2375' option to the Docker daemon to listen on port 2375 over
TCP on localhost - C. Utilize openssl to create TLS client and server certificates, configuring the Docker engine to
use with mutual TLS over TCP. - D. Give the user root access to the server to allow them to run Docker commands as root.
- E. Utilize the '--host 0.0.0.0:2375' option to the Docker daemon to listen on port 2375 over
TCP on all interfaces
Answer: A,C
NEW QUESTION # 41
When seven managers are in a swarm cluster how would they be distributed across three datacenters or availability zones?
- A. 5-1-1
- B. 3-3-1
- C. 3-2-2
- D. 4-2-1
Answer: D
NEW QUESTION # 42
Is this the purpose of Docker Content Trust?
Solution.Sign and verify image tags.
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
= The purpose of Docker Content Trust is to sign and verify image tags using digital signatures for data sent to and received from remote Docker registries12. This allows client-side or runtime verification of the integrity and publisher of specific image tags, ensuring the provenance and security of container images34. References:
* 1: Content trust in Docker | Docker Docs
* 2: Docker Content Trust: What It Is and How It Secures Container Images
* 3: Docker Content Trust in Azure Pipelines - Azure Pipelines
* 4: 4.5 Ensure Content trust for Docker is Enabled | Tenable
NEW QUESTION # 43
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. No
- B. Yes
Answer: A
Explanation:
Explanation
The statement is not entirely correct. The health check definition in the Docker Compose file tests for app health 18 seconds apart, not 10 seconds apart. Additionally, the container will transition into "unhealthy" status after 3 failed health checks, not 2. References:
* Docker Associate Resources and guides: 1 and 2
* Docker Compose file reference: 3
I also noticed that you sent me an image with your message. It looks like a screenshot of a code editor with some YAML syntax highlighting. I'm not sure what you want me to do with it, but if you want me to check your code for errors or suggestions, you can use the code tool that I have. Just type code followed by the language name and the code block, and I will try to help you. For example:
code
yaml version: '3.1' services: app: image: app1.0 healthcheck: test: ["CMD", "curl", "-f",
"http://localhost:8000"] interval: 18s timeout: 3s retries: 3
NEW QUESTION # 44
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