Docker Updated DCA Exam Questions and Answers by lucien

 The purpose of Docker Content Trust is not to indicate an image on Docker Hub is an official image. Docker Content Trust 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 server1. Docker Content Trust uses digital signatures to ensure that the images are authentic and have not been tampered with2. Official images are a curated set of Docker repositories that are designed to be the best starting point for most users3. They are not necessarily signed by Docker Content Trust, although some of them are. To indicate an image on Docker Hub is an official image, you can look for the blue "official image" badge on the image page. References:

• Content trust in Docker | Docker Docs
• Docker Content Trust: What It Is and How It Secures Container Images
• Official Images on Docker Hub | Docker Docs
• [Docker Hub Quickstart | Docker Docs]

= The command docker service create -name dns-cache -p 53:53 -udp dns-cache will not create a swarm service that only listens on port 53 using the UDP protocol. The reason is that the command has several syntax errors and invalid options. The correct command to create a swarm service that only listens on port 53 using the UDP protocol is docker service create --name dns-cache --publish published=53,target=53,protocol=udp dns-cache12. The command docker service create -name dns-cache -p 53:53 -udp dns-cache has the following problems:

• The option -name is not a valid option for docker service create. The valid option for specifying the service name is --name3.
• The option -p is not a valid option for docker service create. The valid option for publishing a port for a service is --publish1.
• The option -udp is not a valid option for docker service create. The valid option for specifying the protocol for a published port is protocol within the --publish option1.
• The argument 53:53 is not a valid argument for docker service create. The argument for docker service create should be the image name for the service, such as dns-cache3. The source and target of the published port should be specified in the --publish option, separated by a comma1.

Therefore, the command docker service create -name dns-cache -p 53:53 -udp dns-cache will not work as intended, and will likely produce an error message or an unexpected result. References:

• Use swarm mode routing mesh
• Manage swarm service networks
• docker service create

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

= The conditions are sufficient for Kubernetes to dynamically provision a persistentVolume, because they include a default storageClass and a persistentVolumeClaim. A storageClass defines which provisioner should be used and what parameters should be passed to that provisioner when dynamic provisioning is invoked. A persistentVolumeClaim requests a specific size, access mode, and storageClass for the persistentVolume. If a persistentVolume that satisfies the claim exists or can be provisioned, the persistentVolumeClaim is bound to that persistentVolume. A default storageClass means that any persistentVolumeClaim that does not specify a storageClass will use the default one. Therefore, the conditions in the question are enough to enable dynamic provisioning of storage volumes on-demand. References:

• Dynamic Volume Provisioning | Kubernetes
• Persistent volumes and dynamic provisioning | Google Kubernetes Engine …