[Jun 19, 2024] DCA Exam Dumps 100% Same Q&A In Your Real Exam
DCA Test Engine Dumps Training With 179 Questions
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NEW QUESTION # 73
Is this a type of Linux kernel namespace that provides container isolation?
Solution. Host
- A. No
- B. Yes
Answer: A
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 # 74
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. No
- B. Yes
Answer: B
Explanation:
Explanation
= Provisioning a Docker config object for each environment is a way to provision configuration to containers at runtime. Docker configs allow services to adapt their behaviour without the need to rebuild a Docker image.
Services can only access configs when explicitly granted by a configs attribute within the services top-level element. As with volumes, configs are mounted as files into a service's container's filesystem1. Docker configs are supported on both Linux and Windows services2. References: Docker Documentation, Configs top-level element
NEW QUESTION # 75
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: docker logs <container-id>
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
Using docker logs <container-id> does not configure a Docker container to export container logs to the logging solution. The docker logs command shows information logged by a running container, such as standard output and standard error streams. It does not send or export container logs to any external service.
References: https://docs.docker.com/engine/reference/commandline/logs/,
https://docs.docker.com/config/containers/logging/
NEW QUESTION # 76
The output of which command can be used to find the architecture and operating system an image is compatible with?
- A. docker image inspect --filter {{.Architecture}} {{.OS}} ' <image-id>
- B. docker image inspect --format {{.Architecture}} {{.OS}} ' <image-id>
- C. docker image ls <image-id>
- D. docker image info <image-id>
Answer: B
NEW QUESTION # 77
Is this a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used?
Solution: net
- A. No
- B. Yes
Answer: A
Explanation:
Explanation
net is not a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used. According to the official documentation, net is one of the namespaces that are enabled by default when using namespaces for isolation.
References: https://docs.docker.com/engine/security/userns-remap/#user-namespace-known-limitations
NEW QUESTION # 78
Does this describe the role of Control Groups (cgroups) when used with a Docker container?
Solution: isolation between resources used by containers
- A. No
- B. Yes
Answer: B
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 # 79
Is this the purpose of Docker Content Trust?
Solution: Enable mutual TLS between the Docker client and server.
- A. No
- B. Yes
Answer: A
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 server12. DCT does not enable mutual TLS between the Docker client and server, which is a different security mechanism that ensures encrypted and authenticated communication between the client and the server3. DCT is based on digital signatures and The Update Framework (TUF) to provide trust over arbitrary collections of data1. References:
* Content trust in Docker | Docker Docs
* Docker Content Trust: What It Is and How It Secures Container Images
* Protect the Docker daemon socket | Docker Docs
NEW QUESTION # 80
In the context of a swarm mode cluster, does this describe a node?
Solution: a physical machine participating in the swarm
- A. No
- B. Yes
Answer: B
Explanation:
A node is a physical or virtual machine running Docker Engine in swarm mode1. A node can be either a manager or a worker, depending on its role in the cluster1. A physical machine participating in the swarm is a node, regardless of its role or availability2. References:
* How nodes work | Docker Docs
* Manage nodes in a swarm | Docker Docs
NEW QUESTION # 81
Is this a way to configure the Docker engine to use a registry without a trusted TLS certificate?
Solution. Set and export the IGNORE_TLS environment variable on the command line.
- A. No
- B. Yes
Answer: A
Explanation:
= 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. This environment variable is not recognized by Docker and has no effect on the TLS verification process1. To use a registry without a trusted TLS certificate, you need to either add the certificate to the system or Docker-specific trust store, or configure the Docker daemon to allow insecure registries23. References:
* Environment variables | Docker Docs
* Verify repository client with certificates | Docker Docs
* Test an insecure registry | Docker Docs
NEW QUESTION # 82
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. No
- B. Yes
Answer: B
Explanation:
Explanation
= The command 'docker service ps http' will list the tasks that are running as part of the 'http' service, as well as the task history1. The task history shows the previous states of the tasks, such as running, shutdown, rejected, etc. This can help you troubleshoot why the service is not registering as healthy, by looking at the current state, error, and ports of each task1. References:
* docker service ps | Docker Docs
* Docker Certified Associate Guide
* DCA Prep Guide
NEW QUESTION # 83
Will this command display a list of volumes for a specific container?
Solution. 'docker container inspect nginx'
- A. No
- B. Yes
Answer: B
Explanation:
Explanation
Using docker container inspect nginx does display a list of volumes for a specific container. The docker container inspect command shows low-level information about one or more containers in JSON format. This information includes various details about the container's configuration, state, network settings, mounts, etc.
To display a list of volumes for a specific container, you can either look at the Mounts section in the JSON output or use --format '{{ .Mounts }}' to filter out only that section. References:
https://docs.docker.com/engine/reference/commandline/container_inspect/,
https://docs.docker.com/engine/reference/commandline/container_inspect/#format-the-output
NEW QUESTION # 84
Does this describe the role of Control Groups (cgroups) when used with a Docker container?
Solution: accounting and limiting of resources
- A. No
- B. Yes
Answer: B
Explanation:
= Control Groups (cgroups) are a feature of the Linux kernel that allow you to limit the access processes and containers have to system resources such as CPU, memory, disk I/O, network, and so on1. Control groups allow Docker Engine to share available hardware resources to containers and optionally enforce limits and constraints2. For example, you can use the docker run command to specify the CPU shares, memory limit, or network bandwidth for a container3. By using cgroups, you can ensure that each container gets the resources it needs and prevent resource starvation or overcommitment4. References:
* Lab: Control Groups (cgroups) | dockerlabs
* Runtime metrics | Docker Docs
* Docker run reference | Docker Docs
* Docker resource management via Cgroups and systemd
NEW QUESTION # 85
Will this Linux kernel facility limit a Docker container's access to host resources, such as CPU or memory?
Solution: namespaces
- A. No
- B. Yes
Answer: B
Explanation:
Explanation
Namespaces are a Linux kernel feature that isolate containers from each other and from the host system. They limit the access of a container to host resources, such as CPU or memory, by creating a separate namespace for each aspect of a container, such as process IDs, network interfaces, user IDs, etc. This way, a container can only see and use the resources that belong to its own namespace, and not those of other containers or the host12. References:
* Isolate containers with a user namespace | Docker Docs
* Docker overview | Docker Docs
NEW QUESTION # 86
The Kubernetes yaml shown below describes a clusterIP service.
Is this a correct statement about how this service routes requests?
Solution: Traffic sent to the IP of this service on port 8080 will be routed to port 80 in a random pod with the label aPP: nginx.
- A. No
- B. Yes
Answer: B
Explanation:
The statement is correct. In the provided Kubernetes YAML, it's defined that traffic sent to the IP of this service on port 8080 will be routed to port 80 in a random pod with the label app: nginx. This is because it's a ClusterIP service type which is meant for internal communication within the cluster, and it uses selectors to route traffic to the correct pods. References: Docker Certified Associate Guide, DCA Prep Guide
NEW QUESTION # 87
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:
= The command docker run -v /data:/mydata --mode readonly ubuntu is not valid because it has some syntax errors. The correct syntax for running a container with a bind mount is docker run [OPTIONS] IMAGE
[COMMAND] [ARG...]. The errors in the command are:
* The option flag for specifying the volume is --volume or -v, not -v. For example, -v
/data:/mydata should be --volume /data:/mydata.
* The option flag for specifying the mode of the volume is --mount, not --mode. For example, --mode readonly should be --mount type=bind,source=/data,target=/mydata,readonly.
* The option flag for specifying the mode of the container is --detach or -d, not --mode. For example, --mode readonly should be --detach.
The correct command for running a container with a bind mount in read-only mode is:
docker run --volume /data:/mydata --mount type=bind,source=/data,target=/mydata,readonly --detach ubuntu This command will run a container using the ubuntu image and mount the host's /data directory to the container's /mydata directory in read-only mode. The container will run in the background (--detach).
References: : docker run reference | Docker Documentation : [Use bind mounts | Docker Documentation]
NEW QUESTION # 88
Will this command list all nodes in a swarm cluster from the command line?
Solution: 'docker swarm nodes'
- A. No
- B. Yes
Answer: A
NEW QUESTION # 89
The Kubernetes yaml shown below describes a clusterIP service.
Is this a correct statement about how this service routes requests?
Solution: Traffic sent to the IP of any pod with the label app: nginx on port 8080 will be forwarded to port 80 in that pod.
- A. No
- B. Yes
Answer: A
Explanation:
The statement is incorrect because it does not mention the service name or the clusterIP address. Traffic sent to the IP of any pod with the label app: nginx on port 8080 will not be forwarded to port 80 in that pod, unless the traffic is coming from another pod within the same cluster that knows the pod IP. To access the service from outside the cluster, the traffic must be sent to the clusterIP address of the service, which is assigned by Kubernetes, and the port 8080 of the service, which is defined in the yaml file. The service will then forward the traffic to one of the selected pods on port 80.
To summarize, the correct statement should be:
Traffic sent to the clusterIP address of the service dca on port 8080 will be forwarded to port 80 in one of the pods with the label app: nginx.
NEW QUESTION # 90
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