DCA Exam Dumps - Docker Certified Associate (DCA) Exam

 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 verify or encrypt the Docker registry TLS, which is a separate mechanism for securing the communication between the Docker client and the registry server. The purpose of DCT is to ensure that the images are not tampered with or maliciously modified by anyone other than the original publisher3. References:

Content trust in Docker | Docker Docs

Docker Content Trust: What It Is and How It Secures Container Images

Automation with content trust | Docker Docs

Creating a Dockerfile for each environment, specifying ports and Docker secrets for certificates is not a way to provision configuration to containers at runtime. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image1. A Dockerfile is used to build an image, not to run a container. Once an image is built, the configuration specified in the Dockerfile cannot be changed at runtime. To provision configuration to containers at runtime, you need to use a different mechanism, such as environment variables, command-line arguments, or config maps234. References:

Dockerfile reference | Docker Docs

Environment variables in Compose | Docker Docs

Override the default command | Docker Docs

Configuration management with Containers | Kubernetes

= Seccomp is a Linux kernel feature that allows you to restrict the actions available within the container. By using a seccomp profile, you can limit the system calls that a container can make, thus enhancing its security and isolation. Docker has a default seccomp profile that blocks some potentially dangerous system calls, such as mount, reboot, or ptrace. You can also pass a custom seccomp profile for a container using the --security-opt option. Seccomp can limit a container’s access to host resources, such as CPU or memory, by blocking or filtering system calls that affect those resources, such as setpriority, sched_setaffinity, or mlock. References:

Seccomp security profiles for Docker

Hardening Docker Container Using Seccomp Security Profile

= The sequence of steps will not completely delete an image from disk in the Docker Trusted Registry. Deleting the image and removing permissions to the repository will only remove the image from the registry’s user interface and prevent unauthorized access to it. However, the image data will still remain on the registry’s storage backend until garbage collection is performed1. Garbage collection is a process that removes unused blobs (layers) from the registry’s storage2. To run garbage collection, the registry must be stopped and the command bin/registry garbage-collect /etc/docker/registry/config.yml must be executed3. Alternatively, the registry can be configured to run garbage collection automatically at regular intervals4. References:

Deleting images | Docker Documentation

Garbage collection | Docker Documentation

How to delete images from a private docker registry? | Stack Overflow

Automating garbage collection | Docker Documentation

= The command kubectl events deployment api is not a valid kubectl command. The correct command to display the events for a deployment object is kubectl get events --field-selector involvedObject.name=api12. This command uses a field selector to filter the events by the name of the involved object, which is the deployment called api. Alternatively, you can use kubectl describe deployment api to see the details and the events for the deployment3. References:

1: kubectl Cheat Sheet | Kubernetes

2: kubernetes - kubectl get events only for a pod - Stack Overflow

3: Kubectl: Get Events & Sort By Time - ShellHacks

 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

A Dockerfile is a text file that contains all the commands a user could run on the command line to create an image1. A Dockerfile is composed of instructions that specify the parent image, the packages to install, the files to copy, the ports to expose, and the commands to run2. A Dockerfile can be used to build a Docker image with the docker build command3. References:

Dockerfile reference | Docker Docs

What is a Dockerfile? A Step-by-Step Guide [2023 Updated] - Simplilearn

How to Build Docker Images with Dockerfile | Linuxize

 = I cannot give you a comprehensive explanation, but I can tell you that the question is about Docker Trusted Registry (DTR), which is a secure and scalable image storagesolution for Docker Enterprise1. DTR allows you to create organizations and teams to manage access to your repositories2. Adding a new user to an organization does not automatically grant them access to any repository. You need to assign them to a team that has the appropriate permissions for the repository you want them to access3. Therefore, the solution suggests adding them to a team in the engineering organization that has read/write access to the engineering/api repository. You will need to understand how DTR works and how to configure access control for repositories to answer this question correctly. References: You can find some useful references for this question in the following links:

Docker Trusted Registry overview

Create and manage organizations and teams

Manage access to repositories