Docker Essentials: A Developer Introduction Cognitive Class Answers[Latest Update‼️]

Hello Learners, Today, we are going to share Docker Essentials: A Developer Introduction Cognitive Class Course Exam Answer launched by IBM. This certification course is totally free of cost✅✅✅ for you and available on Cognitive Class platform.

Here, you will find Docker Essentials: A Developer Introduction Exam Answers in Bold Color which are given below.

These answers are updated recently and are 100% correct✅ answers of all modules and final exam answers of Docker Essentials: A Developer Introduction from Cognitive Class Certification Course.

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Lab 1: Run your first container

Question 1: Containers achieve isolation because of what feature in the Linux kernel?

• Namespaces
• Memory Swap management
• SystemD init system
• Permissions mechanisms

Question 2: What is the difference between a Docker container and a Docker image?

• Nothing: these are two words for the same thing.
• An image is the blueprint for spinning up containers. An image is a TAR of a file system, and a container is a file system plus a set of processes running in isolation.
• Images are used to create the host machine that runs the Docker Engine.
• Images are used only as a backup and restore mechanism for containers.

Question 3: Control groups (cgroups) limit and monitor resources.

• True
• False

Question 4: Which statement is not true about Docker?

• Docker makes it easier to package applications and add to CI/CD pipelines.
• Docker helps you package dependencies with containers.
• Docker invented containers and Linux namespaces.
• Docker simplifies container technology to make creating and running containers easier.

Question 5: What tool makes it possible to run Docker containers on operating systems other than Linux?

• LinuxByte
• OSContainers
• Docker Swarm
• LinuxKit

Lab 2: Add CI/CD value with Docker images

Question 1 : Which file should you use to create reproducible builds for Docker images?

• docker.yml
• docker.config
• Dockerfile
• README.md

Question 2 : To rebuild and re-push images quickly, you should optimize your Dockerfile for what?

• Reproducibility: ensures your Dockerfile will create the same image every time it is built
• Documentation: helps other engineers build and push images faster
• Time to market: enables business users to get their features out faster
• The layer cache: put lines that change more frequently near the end of the file

Question 3 : You must use Docker Hub as the central registry to share the Docker images that you create.

• True
• False

Question 4 : What’s the purpose of the FROM line in a dockerfile? Select all that apply.

• It executes commands needed to set up your image for an application.
• It’s required as the first line in a Dockerfile.
• It copies a file into a directory.
• It specifies the starting image to build other image layers on top of.

Question 5 : What does this command do: $ docker system prune.

• Stops and removes containers
• Stops running containers
• Retrieves a list of running containers
• Removes containers that are already stopped

Lab 3. Orchestrate applications with Docker Swarm

Question 1 : What is the operational model used by Docker Swarm for managing a cluster?

• Declarative
• Imperative
• Closed-source
• Nonexistent

Question 2 : What effect does the routing mesh have on a Docker swarm cluster?

• Commands, such as “docker service create,” that are sent to any node on the cluster will be routed to a manager that can respond to those commands.
• Requests that are sent to a published port on any node of the swarm will automatically be routed to a node that is running a container for that service.
• Every service that is created on the cluster will schedule at least one container for every node in the cluster to ensure global availability.
• You can enable the routing mesh to use layer-7 load balancing in front of your running containers.

Question 3 : The “docker swarm init command” generates a join token. What is the purpose of that token?

• It allows you to remotely control production applications.
• It initializes a swarm.
• It makes sure that no malicious nodes join the swarm.
• It outputs nodes in a swarm.

Question 4 : When you run the following command, which of the following events does not occur?

$ docker service update –replicas=5 –detach=true nginx1

nginx1

• The state of the service is updated to 5 replicas, which is stored in the swarm’s internal storage.
• Docker Swarm recognizes that the number of replicas that is scheduled now does not match the declared state of 5.
• This command checks aggregated logs on the updated replicas.
• Docker Swarm schedules 5 more tasks (containers) in an attempt to meet the declared state for the service.

Question 5 : The more manager nodes you have, the easier it is to achieve a consensus on the state of a cluster.

• True
• False

Final Exam Answers

Question 1 :  What is one advantage of isolation that is provided by containers?

• Container isolation provides a mechanism for immutable infrastructure.
• Containers running in isolation means that you don’t have to deal with conflicting dependencies that are installed on the host or other containers.
• Isolated containers make it easier to monitor applications running inside of containers.
• Each isolated container provides you with an SSH server that can be used for debugging or automation purposes.

Question 2 :  What factors should you consider when you choose your FROM image?

• Size
• Security
• Source
• All of these

Question 3 :  What is the best way to distribute a Dockerized application to different environments?

• Maven Nexus repository
• Docker registry
• Source control
• Any of these

Question 4 :  What is a good starting point for the number of manager nodes in a cluster?

• 3
• 1
• 4
• 10

Question 5 :  Running containerized applications in production can come with a variety of problems. Which of the following items is not a problem of running a containerized application in production?

• Scheduling containers across a distributed cluster
• High availability
• Scaling
• “Works on my machine” syndrome

Question 6 :  What is one advantage of using containers across different environments?

• Deploying containers only once, and Docker will deploy across all environments automatically
• Avoiding environmental drift caused by maintaining multiple environments correct
• Redeploying containers
• Creating independent applications

Question 7 :  You need an SSH server to get a bash shell inside a container.

• True
• False

Question 8 :  What technologies are behind Docker’s image layering system?

• Linux namespaces and control groups
• Storage driver plugins
• Union file system and copy-on-write
• Docker build and push caching

Question 9 :  What is the result of running the command “docker run ubuntu:15.04” 1000 times on your workstation?

• Your workstation will run 1000 Ubuntu containers and will likely handle this just fine.
• Your workstation will crash from being out of space if it’s running with 100 GB of storage or less.
• Your workstation will crash from being out of memory if it’s running with less than 4 GB of RAM.
• The developer-friendly interface of the Docker CLI will prevent you from doing something so silly.

Question 10:  Open-source container orchestration platforms, such as Docker Swarm and Kubernetes, provide what to their users?

• A way to orchestrate different flavors of the same application in a way that maximizes reuse
• A fully hosted solution that is production-ready for deploying enterprise grade applications
• An easy-to-use GUI for operators to click and deploy applications
• A platform to help solve problems of running distributed containerized applications in production, such as high availability, scaling, fault tolerance, and scheduling

Conclusion

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