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Most Recent Docker DCA Exam Dumps

 

Prepare for the Docker Certified Associate Exam exam with our extensive collection of questions and answers. These practice Q&A are updated according to the latest syllabus, providing you with the tools needed to review and test your knowledge.

QA4Exam focus on the latest syllabus and exam objectives, our practice Q&A are designed to help you identify key topics and solidify your understanding. By focusing on the core curriculum, These Questions & Answers helps you cover all the essential topics, ensuring you're well-prepared for every section of the exam. Each question comes with a detailed explanation, offering valuable insights and helping you to learn from your mistakes. Whether you're looking to assess your progress or dive deeper into complex topics, our updated Q&A will provide the support you need to confidently approach the Docker DCA exam and achieve success.

The questions for DCA were last updated on Feb 18, 2025.
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Question No. 1

Is this a way to configure the Docker engine to use a registry without a trusted TLS certificate?

Solution: List insecure registries in the 'daemon.json configuration file under the \insecure-registries' key.

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Correct Answer: A

Docker allows the use of insecure registries through a specific configuration in the Docker daemon. By listing the insecure registries in the 'daemon.json' configuration file under the 'insecure-registries' key, Docker can interact with these registries even without a trusted TLS certificate1. This is particularly useful when setting up a private Docker registry1. However, it's important to note that this configuration bypasses the security provided by TLS, and should be used with caution1.


Question No. 2

Are these conditions sufficient for Kubernetes to dynamically provision a persistentVolume, assuming there are no limitations on the amount and type of available external storage?

Solution: A persistentVolumeClaim is created that specifies a pre-defined storageClass.

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Correct Answer: A

= The conditions are sufficient for Kubernetes to dynamically provision a persistentVolume, because a storageClass defines the provisioner and parameters for creating a volume on-demand. A persistentVolumeClaim that specifies a storageClass triggers the dynamic provisioning process, and Kubernetes will automatically create and bind a persistentVolume that matches the request. This eliminates the need for manual intervention by cluster administrators to provision storage volumes.Reference:

Dynamic Volume Provisioning | Kubernetes

Persistent volumes and dynamic provisioning | Google Kubernetes Engine ...

Dynamic Provisioning and Storage Classes in Kubernetes


Question No. 3

One of several containers in a pod is marked as unhealthy after failing its livenessProbe many times. Is this the action taken by the orchestrator to fix the unhealthy container?

Solution: The controller managing the pod is autoscaled back to delete the unhealthy pod and alleviate load.

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Correct Answer: B

: = The livenessProbe is a mechanism that checks if the container is alive and healthy, and restarts it if it fails1.The orchestrator is the component that manages the deployment and scaling of containers across a cluster of nodes2.The action taken by the orchestrator to fix the unhealthy container isnotto autoscale back and delete the pod, but torecreatethe pod on the same or a different node3. This ensures that the desired number of replicas for the pod is maintained, and that the pod can resume its normal operation. Autoscaling back and deleting the pod would reduce the availability and performance of the service, and would not necessarily alleviate the load.


Configure Liveness, Readiness and Startup Probes | Kubernetes

What is a Container Orchestrator? | Docker

Pod Lifecycle | Kubernetes

I hope this helps you understand the concept of livenessProbe and orchestrator, and how they work with Docker and Kubernetes. If you have any other questions related to Docker, please feel free to ask me.

Question No. 4

Is this a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used?

Solution. pid

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Correct Answer: B

= The pid namespace is not a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used.The pid namespace is one of the six namespaces that are enabled by default when you run a container with Docker1.The pid namespace isolates the process ID number space, meaning that processes in different pid namespaces can have the same PID2.This allows containers to have their own init process with PID 1 and to limit the visibility and interaction of processes between containers and the host3. To disable the pid namespace, you need to use the --pid option with the docker run command and specify the host or another container as the pid mode.Reference:

Docker run reference | Docker Docs

pid_namespaces(7) - Linux manual page - man7.org

Building containers by hand: The PID namespace - Enable Sysadmin

[Share host and container processes with --pid | Docker Docs]


Question No. 5

Seven managers are in a swarm cluster.

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

Solution: 5-1-1

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Correct Answer: B

= I cannot give you a comprehensive explanation, but I can tell you that the question is about Docker Swarm, which is a native clustering solution for Docker1.Docker Swarm allows you to create a group of Docker hosts, called nodes, that work together as a single virtual system1. Nodes can be either managers or workers.Managers are responsible for maintaining the cluster state and orchestrating services, while workers are responsible for running the tasks assigned by managers1.A swarm cluster should have an odd number of managers to avoid split-brain scenarios and ensure high availability2.However, having too many managers can also degrade performance and increase the risk of failures2.Therefore, the recommended number of managers is between 3 and 72. The solution suggests distributing the 7 managers across 3 datacenters or availability zones as 5-1-1, meaning 5 managers in one zone, and 1 manager in each of the other two zones. This may not be the optimal distribution, as it creates a single point of failure in the zone with 5 managers.If that zone goes down, the remaining 2 managers will not be able to form a quorum and the cluster will become unavailable3.A better distribution may be 3-2-2 or 2-2-2-1, as they provide more redundancy and resilience3. You will need to understand how Docker Swarm works and how to design a highly available cluster to answer this question correctly.Reference: You can find some useful references for this question in the following links:

Docker Swarm overview

Swarm mode key concepts

Swarm mode best practices


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