DCA Exam Dumps - Docker Certified Associate (DCA) Exam

They provide granular control over where pods (or in this case, containers) are scheduled, based on the labels of the nodes1.In the context of Docker Swarm, this means that you could use node affinities to ensure that development and production containers are scheduled on separate nodes, thus meeting the company’s security policy requirements12345.

Adding a new user to the engineering organization in DTR will not automatically grant them read/write access to the engineering/api repository. This is because the repository permissions are not inherited from the organization level, but are configured separately for each repository. Therefore, to grant read/write access to the new user, you need to add them directly to the list of users with read/write access under the repository’s Permissions tab. References:

Docker Trusted Registry - Manage access to repositories

Docker Certified Associate (DCA) Study Guide - Domain 3: Image Creation, Management, and Registry

https://docs.docker.com/ee/dtr/user/manage-repos/#manage-access-to-repositories

https://success.docker.com/certification/study-guides/dca-study-guide#domain-3-image-creation-management-and-registry-20-of-exam

 This command will not display a list of volumes for a specific container, as it will show detailed information on the container itself, such as its configuration, network settings, state, and log path1. To display a list of volumes for a specific container, you need to use the --format option with a custom template that filters the output by the Mounts field2. For example, the following command will show the source and destination of the volumes mounted in the nginx container:

docker container inspect --format=' { {range .Mounts}} { {.Source}} -> { {.Destination}} { {end}}' nginx References:

docker container inspect | Docker Docs

How to Use Docker Inspect Command - Linux Handbook

 Adding all the resources to the default namespace is not a way to accomplish this, because it would not isolate the resources for each application. Instead, the teams should use namespaces, which are a mechanism to organize resources in a Kubernetes cluster. Namespaces provide a scope for names of resources and a way to attach authorization and policy to a subset of the cluster. By creating a separate namespace for each application, the teams can ensure that their resources are grouped together and not accessible by other teams or applications.

Tagging the image with ‘nginx:immutable’ is not how a user can prevent an image, such as ‘nginx:latest’, from being overwritten by another user with push access to the repository.Tagging the image with ‘nginx:immutable’ will only create a new tag for the image, but it will not prevent the original tag from being overwritten. To prevent an image tag from being overwritten in Docker Trusted Registry, the user can use the DTR web UI to make the tag immutable1. This will prevent anyone from pushing a new image with the same tag, even if they have push access to the repository1. Alternatively, the user can also use the DTR API to make the tag immutable2. References: Prevent tags from being overwritten), DTR API reference)

= Docker will block this command if you configure the local Docker engine to enforce content trust by setting the environment variable DOCKER_CONTENT_TRUST=1. This means that you can only pull, run, or build with trusted images that have been signed using Docker Content Trust (DCT)1. DCT is a feature that allows you to use digital signatures to verify the integrity and the publisher of specific image tags2. If myorg/myimage:1.0 is unsigned, it means that it does not have a valid signature from the image publisher or a trusted delegate. Therefore, Docker will not allow you to build an image from a Dockerfile that begins with FROM myorg/myimage:1.0, as it cannot verify the source or the content of the base image. You will get an error message like this:

No valid trust data for 1.0

To avoid this error, you need to either disable DCT by setting DOCKER_CONTENT_TRUST=0, or use a signed image tag as the base image in your Dockerfile3. 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

 = Uninstalling the ‘docker-ce’ package before installing the ‘docker-ee’ package will not upgrade Docker Engine CE to Docker Engine EE. It will only remove the existing Docker Engine CE installation and install a new Docker Engine EE installation. This means that any existing containers, images, volumes, networks, and other Docker resources will be lost. To upgrade Docker Engine CE to Docker Engine EE without losing any data, youneed to use the migration tool provided by Docker1 or follow the steps described in the Docker documentation2 or other online guides34. References:

1: Migrate to Engine 1.10 | Docker Docs

2: Install Docker Engine | Docker Docs

3: Switching Docker 18.09 Community Edition to Enterprise Engine with no …

4: How to upgrade Docker 18.09 Community Edition to Docker Enterprise 18.09

Creating one pod and adding all the resources needed for each application is not a good way to accomplish the goal of grouping Kubernetes-specific resources for each application. This is because pods are the smallest unit of a Kubernetes application, and they are designed to run a single container or a set of tightly coupled containers that share the same network and storage resources1. Pods are ephemeral and can be created and destroyed by the Kubernetes system at any time. Therefore, putting multiple applications in one pod would make them harder to manage, scale, and update independently. A better way to accomplish the goal is to use namespaces, which are logical clusters within a physical cluster that can isolate resources, policies, and configurationsfor different applications2. Namespaces can also help organize secrets, which are Kubernetes objects that store sensitive information such as passwords, tokens, and keys3. References:

Pods | Kubernetes

Namespaces | Kubernetes

Secrets | Kubernetes