Pass the Docker Certified Associate DCA Questions and answers with ExamsMirror

= SAML is a supported user authentication method for Universal Control Plane (UCP). UCP has its own built-in authentication mechanism and integrates with LDAP and Active Directory. It also supports Role Based Access Control (RBAC) and Docker Content Trust. UCP allows you to configure SAML as an authentication method and connect it to your Identity Provider (IdP). You need to provide the Entity ID and the ACS URL fromUCP to your IdP, and the SAML Sign-on URL and the x509 Certificate from your IdP to UCP12. References:

SAML | Docker Docs

Configure Single Sign-On | Docker Docs

= The conditions are not sufficient for Kubernetes to dynamically provision a persistentVolume, because they are missing a StorageClass object. A StorageClass object defines which provisioner should be used and what parameters should be passed to that provisioner when dynamic provisioning is invoked. A persistentVolumeClaim must specify the name of a StorageClass in its storageClassName field to request a dynamically provisioned persistentVolume. Without a StorageClass, Kubernetes cannot determine how to provision the storage for the claim. References:

Dynamic Volume Provisioning | Kubernetes

Persistent volumes and dynamic provisioning | Google Kubernetes Engine …

Dynamic Provisioning and Storage Classes in Kubernetes or Dynamic Provisioning and Storage Classes in Kubernetes

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 Notaryserver1. DCT is enabled by setting the environment variable DOCKER_CONTENT_TRUST=1 on the Docker client. When DCT is enabled, the Docker client will only pull, run, or build images that have valid signatures for a specific tag2. However, DCT does not apply to the docker image import command, which allows users to import an image or a tarball with a repository and tag from a file or STDIN3. Therefore, if myorg/myimage:1.0 is unsigned, Docker will not block the docker image import myorg/myimage:1.0 command, even if DCT is enabled. This is because the docker image import command does not interact with a registry or a Notary server, and thus does not perform any signature verification. However, this also means that the imported image will not have any trust data associated with it, and it will not be possible to push it to a registry with DCT enabled, unless it is signed with a valid key. References:

Content trust in Docker

Automation with content trust

[docker image import]

[Content trust and image tags]

 The command docker service create -name dns-cache -p 53:53 -service udp dns-cache is not valid because it has some syntax errors. The correct syntax for creating a swarm service is docker service create [OPTIONS] IMAGE [COMMAND] [ARG...]. The errors in the command are:

There should be a space between the option flag and the option value. For example, -name dns-cache should be -name dns-cache.

The option flag for specifying the service mode is -mode, not -service. For example, -service udp should be -mode udp.

The option flag for specifying the port mapping is --publish or -p, not -p. For example, -p 53:53 should be --publish 53:53.

The correct command for creating a swarm service that only listens on port 53 using the UDP protocol is:

docker service create --name dns-cache --publish 53:53/udp dns-cache

This command will create a service called dns-cache that uses the dns-cache image and exposes port 53 on both the host and the container using the UDP protocol.

[docker service create | Docker Documentation] : [Publish ports for services | Docker Documentation]

 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.

 The command docker network create -d overlay -o encrypted=true  will ensure that overlay traffic between service tasks is encrypted. This command creates an overlay network with the encryption option enabled, which means that Docker will create IPSEC tunnels between all the nodes where tasks are scheduled for services attached to the overlay network. These tunnels use the AES algorithm in GCM mode and manager nodes automatically rotate the keys every 12 hours1. This way, thedata exchanged between containers on different nodes on the overlay network is secured. References:

Overlay network driver

= Manually downloading the ‘docker-ee’ package will not upgrade Docker Engine CE to Docker Engine EE. Docker Engine CE and Docker Engine EE are two different products with different installation methods and features. Docker Engine CE is a free and open source containerization platform, while Docker Engine EE is a subscription-based enterprise-grade platform that offers additional features such as security scanning, certified plugins, and support12. To upgrade from Docker Engine CE to Docker Engine EE, you need to uninstall Docker Engine CE and install Docker Engine EE following the official documentation3. References:

What is the exact difference between Docker EE (Enterprise Edition), Docker CE (Community Edition) and Docker (Custom Support) - Stack Overflow

Difference between Docker Community Edition (CE) vs Docker Enterprise Edition (EE) in 2020

Install Docker Engine | Docker Docs

= The command docker volume inspect nginx will not display a list of volumes for a specific container. This is because docker volume inspect expects one or more volume names as arguments, nota container name1. To display a list of volumes for a specific container, you can use the docker inspect command with the --format option and a template that extracts the volume information fromthe container JSON output2. For example, to display the source and destination of the volumes mounted by the container nginx, you can use the following command:

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

docker volume inspect | Docker Docs

docker inspect | Docker Docs