(2024) DCA Dumps and Practice Test (169 Questions)
Guide (New 2024) Actual Docker DCA Exam Questions
NEW QUESTION # 35
When an application being managed by UCP fails, you would like a summary of all requests made to the UCP API in the hours leading up to the failure.
What must be configured correctly beforehand for this to be possible?
- A. UCP logging levels must be set to the info' or debug' level.
- B. All engines in the cluster must have their log driver set to the metadata' or request' level.
- C. Set the logging level in theconfig object for the ucp-kube-api-server container to warning or higher.
- D. UCP audit logs must be set to the metadata' or request' level.
Answer: D
NEW QUESTION # 36
Will This command list all nodes in a swarm cluster from the command line?
Solution. 'docker swarm nodes'
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
This command does not list all nodes in a swarm cluster from the command line. The docker swarm command manages swarm operations, such as initializing or joining a swarm, updating the swarm configuration, etc. It does not show information about nodes or services. To list all nodes in a swarm cluster from the command line, you need to use docker node ls command. This command shows information about all the nodes that are part of the swarm, such as their ID, hostname, status, availability, etc. References:
https://docs.docker.com/engine/reference/commandline/swarm/,
https://docs.docker.com/engine/reference/commandline/node_ls/
NEW QUESTION # 37
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 --filter {{.Architecture}} {{.OS}} ' <image-id>
- C. docker image inspect --format {{.Architecture}} {{.OS}} ' <image-id>
- D. docker image ls <image-id>
Answer: C
NEW QUESTION # 38
In Docker Trusted Registry, how would a user prevent an image, for example 'nginx:latest' from being
overwritten by another user with push access to the repository?
- A. Use the DTR web UI to make the tag immutable.
- B. Tag the image with 'nginx:immutable'
- C. Keep a backup copy of the image on another repository.
- D. Remove push access from all other users.
Answer: A
NEW QUESTION # 39
Is this a type of Linux kernel namespace that provides container isolation?
Solution: Network
- A. No
- B. Yes
Answer: A
NEW QUESTION # 40
Will a DTR security scan detect this?
Solution.private keys copied to the image
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
= A DTR security scan will detect private keys copied to the image. DTR security scan is a feature of Docker Trusted Registry (DTR) that scans images to detect any security vulnerability1. DTR security scan uses the open source tool SecretScanner2 to find unprotected secrets in container images or file systems. SecretScanner can match the contents of images against a database of approximately 140 secret types, including private keys3. Therefore, if an image contains private keys, DTR security scan will report them as potential secrets and alert the user to remove them from the image. References:
* Scan images for vulnerabilities | Docker Docs
* GitHub - deepfence/SecretScanner: :unlock: Find secrets and passwords ...
* SecretScanner/deepfence_secret_scanner.py at main deepfence/SecretScanner
NEW QUESTION # 41
Does this describe the role of Control Groups (cgroups) when used with a Docker container?
Solution: isolation between resources used by containers
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Control Groups (cgroups) are a Linux kernel feature that allow you to limit, modify, or allocate resources as needed1. Docker uses cgroups to isolate the resources used by containers, such as CPU, memory, disk I/O, network, etc2. This means that each container can have its own set of resource limits and constraints, and that the containers cannot interfere with each other or with the host system2. This improves the security, performance, and reliability of the containers and the system as a whole. References:
* Lab: Control Groups (cgroups) | dockerlabs
* Docker run reference | Docker Docs
NEW QUESTION # 42
Is this a type of Linux kernel namespace that provides container isolation?
Solution.Host
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
= Host is not a type of Linux kernel namespace that provides container isolation. Linux namespaces are a feature of the Linux kernel that partitions kernel resources such that one set of processes sees one set of resources while another set of processes sees a different set of resources1. There are eight kinds of namespaces available: Mount, Process, User, Network, UTS, IPC, Cgroup, and Time1. Host is a parameter that can be used to run a container in the host's network namespace, which means the container shares the same network interfaces and configuration as the host2. References:
* Linux namespaces - Wikipedia
* Network settings | Docker Documentation
NEW QUESTION # 43
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 a collection for for each application.
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
= Creating a collection for each application is not a way to accomplish this. A collection is a term used by Ansible to describe a package of related content that can be used to automate the management of Kubernetes resources1. A collection is not a native Kubernetes concept and does not group resources together within the cluster. To group Kubernetes-specific resources, such as secrets, for each application, you need to use namespaces. A namespace is a logical partition of the cluster that allows you to isolate resources and apply policies to them2. You can create a namespace for each application and store the secrets and other resources in that namespace. This way, you can prevent conflicts and limit access to the resources of each application. To create a namespace, you can use the kubectl create namespace command or a yaml file2. To create a secret within a namespace, you can use the kubectl create secret command with the --namespace option or a yaml file with the metadata.namespace field3. References:
* Kubernetes Collection for Ansible - GitHub
* Namespaces | Kubernetes
* Secrets | Kubernetes
* Managing Secrets using kubectl | Kubernetes
NEW QUESTION # 44
If installing Docker using devicemapper for storage with the Intent to run production workloads, how should devicemapper be configured
- A. direct-lvm
- B. overlay-lvm
- C. aufs-lvm
- D. loop-lvm
Answer: A
NEW QUESTION # 45
An application image runs in multiple environments, with each environment using different certificates and ports.
Is this a way to provision configuration to containers at runtime?
Solution: Provision a Docker config object for each environment.
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Provisioning a Docker config object for each environment is a way to provision configuration to containers at runtime. A Docker config object is a file that contains configuration data for an application or service. It can be created using the docker config create command and then attached to a service using the --config flag of the docker service create or update command. This allows different configurations to be applied to different environments without changing the image or the code of the application. References:
https://docs.docker.com/engine/swarm/configs/,
https://docs.docker.com/engine/reference/commandline/config_create/
NEW 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: resource reservation
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
Resource reservation is a feature that allows you to specify the amount of CPU and memory resources that a service or a container needs. This helps the scheduler to place the service or the container on a node that has enough available resources. However, resource reservation does not control which node the service or the container runs on, nor does it enforce any separation or isolation between different services or containers.
Therefore, resource reservation cannot be used to schedule containers to meet the security policy requirements.
References:
* [Reserve compute resources for containers]
* [Docker Certified Associate (DCA) Study Guide]
https://docs.docker.com/config/containers/resource_constraints/
https://success.docker.com/certification/study-guides/dca-study-guide
NEW QUESTION # 47
Is this an advantage of multi-stage builds?
Solution. better logical separation of Dockerfile instructions for increased readability
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
Better logical separation of Dockerfile instructions for increased readability is not an advantage of multi-stage builds. Multi-stage builds are a feature that allows you to use multiple FROM statements in your Dockerfile.
Each FROM statement begins a new stage of the build. You can selectively copy artifacts from one stage to another, leaving behind everything you don't want in the final image. The main advantage of multi-stage builds is that they allow you to reduce the size of your final image by only including the essential components and dependencies. Another advantage of multi-stage builds is that they allow you to optimize the build cache by grouping similar instructions in each stage. Better logical separation of Dockerfile instructions for increased readability is not an inherent advantage of multi-stage builds, as it depends on how you write and organize your Dockerfile. References: https://docs.docker.com/develop/develop-images/multistage-build/,
https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#use-multi-stage-builds
NEW QUESTION # 48
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. No
- B. Yes
Answer: A
NEW QUESTION # 49
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 # 50
Your organization has a centralized logging solution, such as Sptunk.
Will this configure a Docker container to export container logs to the logging solution?
Solution. docker system events- -filter splunk
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
This does not configure a Docker container to export container logs to the logging solution. The docker system events command shows information about real-time events in the Docker daemon. The --filter flag allows you to filter the output by various criteria, such as type, action, image, container, etc. However, splunk is not a valid filter value and will cause an error. To configure a Docker container to export container logs to the logging solution, you need to use the --log-driver and --log-opt flags when creating or running the container.
These flags allow you to specify which logging driver and options to use for the container. For example, to use Splunk as the logging driver, you can use --log-driver splunk and provide the Splunk URL, token, and other options using --log-opt. References: https://docs.docker.com/engine/reference/commandline/system_events/,
https://docs.docker.com/config/containers/logging/configure/,
https://docs.docker.com/config/containers/logging/splunk/
NEW QUESTION # 51
Will this command mount the host's '/data' directory to the ubuntu container in read-only mode?
Solution: 'docker run -v /data:/mydata --mode readonly ubuntu'
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
This command will not mount the host's '/data' directory to the ubuntu container in read-only mode, because it has an incorrect option for making the volume read-only. According to the official documentation, the correct command should be:
docker run -v /data:/mydata:ro ubuntu
The incorrect option is:
The --mode flag does not exist and should be replaced by a :ro suffix to make the volume read-only.
References: https://docs.docker.com/engine/reference/commandline/run/#mount-volume-v-read-only
https://docs.docker.com/storage/volumes/#use-a-read-only-volume
NEW QUESTION # 52
Which of the following namespaces is disabled by default and must be enabled at Docker engine runtime in order to be used?
- A. net
- B. pid
- C. user
- D. mnt
Answer: C
NEW QUESTION # 53
Does this describe the role of Control Groups (cgroups) when used with a Docker container?
Solution: role-based access control to clustered resources
- A. No
- B. Yes
Answer: A
NEW QUESTION # 54
A user is having problems running Docker. Which of the following will start Docker in debug mode?
- A. Start the 'dockerd' process manually with the '--logging' flag set to debug
- B. Start the 'dockerd' process manually with the '--raw-logs' flag set to debug
- C. Set the logging key to debug in the 'daemon.json' file.
- D. Set the debug key to true in the 'daemon.json' file.
Answer: D
NEW QUESTION # 55
Is this a type of Linux kernel namespace that provides container isolation?
Solution: Network
- A. Yes
- B. No
Answer: A
Explanation:
Explanation
Network is a type of Linux kernel namespace that provides container isolation. A network namespace provides isolation of network devices, stacks, ports, etc. Each network namespace has its own network devices, IP addresses, IP routing tables, /proc/net directory, port numbers, etc. Docker uses network namespaces to give each container its own virtual network interface and IP address. References: https://docs.docker.com/network/,
https://man7.org/linux/man-pages/man7/network_namespaces.7.html
NEW QUESTION # 56
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 inspect http'
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
= The 'docker inspect' command returns low-level information on Docker objects, such as containers, images, networks, etc1 It does not show the list of historical tasks for a service. To view the list of tasks for a service, you need to use the 'docker service ps' command 2. For example, to see the tasks for the 'http' service, you would run 'docker service ps http'. This would show the ID, name, image, node, desired state, current state, and error of each task 2. References: Docker inspect | Docker Docs, Docker service ps | Docker Docs
NEW QUESTION # 57
......
The DCA exam covers a range of topics related to Docker, including containerization, orchestration, networking, security, and storage. DCA exam is designed to test the candidate's ability to work with Docker in real-world scenarios, and it includes both multiple-choice and interactive tasks. DCA exam is computer-based and can be taken online from anywhere in the world, making it accessible to candidates from all backgrounds and locations.
DCA Exam Dumps Pass with Updated 2024 Certified Exam Questions: https://www.examdumpsvce.com/DCA-valid-exam-dumps.html
DCA Exam Questions - Real & Updated Questions PDF: https://drive.google.com/open?id=18ciucz0JaQMZKKlmDwOv_18euNk3Q7DP
