Docker DCA Practice Test - Questions Answers, Page 6

= The commanddocker run -v /data:/mydata --mode readonly ubuntuisnot validbecause it has somesyntax errors. The correct syntax for running a container with a bind mount isdocker run [OPTIONS] IMAGE [COMMAND] [ARG...]. The errors in the command are:

The option flag for specifying thevolumeis--volumeor-v, not-v. For example,-v /data:/mydatashould be--volume /data:/mydata.

The option flag for specifying themodeof the volume is--mount, not--mode. For example,--mode readonlyshould be--mount type=bind,source=/data,target=/mydata,readonly.

The option flag for specifying themodeof the container is--detachor-d, not--mode. For example,--mode readonlyshould be--detach.

The correct command for running a container with a bind mount in read-only mode is:

docker run --volume /data:/mydata --mount type=bind,source=/data,target=/mydata,readonly --detach ubuntu

This command will run a container using theubuntuimage and mount the host's/datadirectory to the container's/mydatadirectory in read-only mode. The container will run in the background (--detach).

= The command 'docker run --volume /data:/mydata:ro ubuntu' will mount the host's '/data' directory to the ubuntu container in read-only mode.The --volume or -v option allows you to mount a host directory or a file to a container as a volume1. The syntax for this option is:

-v|--volume=[host-src:]container-dest[:<options>]

The host-src can be an absolute path or a name value. The container-dest must be an absolute path.The options can be a comma-separated list of mount options, such as ro for read-only, rw for read-write, z or Z for SELinux labels, etc1.In this case, the host-src is /data, the container-dest is /mydata, and the option is ro, which means the container can only read the data from the volume, but not write to it2.This can be useful for sharing configuration files or other data that should not be modified by the container3.Reference:

Use volumes | Docker Documentation

Docker run reference | Docker Documentation

Docker - Volumes - Tutorialspoint

The statement is not entirely correct. The health check definition in the Docker Compose file tests for app health 18 seconds apart, not 10 seconds apart. Additionally, the container will transition into ''unhealthy'' status after 3 failed health checks, not 2.Reference:

Docker Associate Resources and guides:1and2

Docker Compose file reference:3

I also noticed that you sent me an image with your message. It looks like a screenshot of a code editor with some YAML syntax highlighting. I'm not sure what you want me to do with it, but if you want me to check your code for errors or suggestions, you can use thecodetool that I have. Just typecodefollowed by the language name and the code block, and I will try to help you. For example:

code yaml version: '3.1' services: app: image: app1.0 healthcheck: test: [''CMD'', ''curl'', ''-f'', ''http://localhost:8000''] interval: 18s timeout: 3s retries: 3

= I cannot give you a comprehensive explanation, but I can tell you that the statement is not entirely correct. The health check definition in the Docker Compose file tests for app health 18 seconds apart, not 10 seconds apart. Additionally, if the test fails, the container will be restarted 3 times before it gets rescheduled, not 4 times.Reference:

Docker Associate Resources and guides:1and2

Docker Compose health check documentation:3

Docker health check documentation:4

I hope this helps you prepare for your DCA exam. If you want to practice more questions, you can check out some of the online courses that offer practice exams, such as5,6,7,8, and9. Good luck!

A DTR security scan will detect licenses for known third party binary components.This is because DTR security scan uses a database of vulnerabilities and licenses that is updated regularly from Docker Server1.DTR security scan can identify the components and versions of the software packages that are present in the image layers, and report any known vulnerabilities or licenses associated with them2.This can help users to comply with the licensing requirements and avoid potential legal issues3.Reference:

Set up vulnerability scans | Docker Docs

Scan images for vulnerabilities | Docker Docs

Container Security 101 --- Scanning images for Vulnerabilities

The command 'kubectl get pods -I env=development' willnotdisplay all the pods in the cluster that are labeled as 'env: development'.This is because the -I flag isnota valid option for kubectl get pods1.The correct flag to use is --selector or -l, which allows you to filter pods by labels2. Therefore, the correct command to display all the pods in the cluster that are labeled as 'env: development' is:

kubectl get pods --selector env=development

or

kubectl get pods -l env=development

kubectl Cheat Sheet | Kubernetes

Labels | Kube by Example

I hope this helps you understand the command and the label, and how they work with Kubernetes and pods. If you have any other questions related to Docker, please feel free to ask me.

= The commandkubectl get pods --all-namespaces -label env=developmentisnot validbecause it has asyntax error. The correct syntax for listing pods with a specific label iskubectl get pods --all-namespaces --selector label=valueorkubectl get pods --all-namespaces -l label=value. The error in the command is:

The option flag for specifying thelabel selectoris--selectoror-l, not-label. For example,-label env=developmentshould be--selector env=developmentor-l env=development.

The correct command for listing all the pods in the cluster that are labeled asenv: developmentis:

kubectl get pods --all-namespaces --selector env=development

This command will display the name, status, restarts, and age of the pods that have the labelenv: developmentin all namespaces.

The command 'kubectl get pods --all-namespaces -I env=development' does not display all the pods in the cluster that are labeled as 'env: development'. The reason is that the flag -I is not a valid option for kubectl get pods.The correct flag to use is --selector or -l, which allows you to filter pods by labels1.Labels are key-value pairs that can be attached to Kubernetes objects to identify, group, or select them2. For example, to label a pod with env=development, one can run:

kubectl label pods my-pod env=development

To display all the pods that have the label env=development, one can run:

kubectl get pods --selector env=development

or

kubectl get pods -l env=development

The --all-namespaces flag can be used to list pods across all namespaces3. Therefore, the correct command to display all the pods in the cluster that are labeled as 'env: development' is:

kubectl get pods --all-namespaces --selector env=development

or

kubectl get pods --all-namespaces -l env=developmentReference:

kubectl Cheat Sheet | Kubernetes

Labels and Selectors | Kubernetes

kubectl get | Kubernetes

= The commanddocker container inspect nginxwill display a list of volumes for the specific container named nginx.The output of the command will include a section called ''Mounts'' that shows the source, destination, mode, type, and propagation of each volume mounted in the container1.For example, the following output shows that the container nginx has two volumes: one is a bind mount from the host's /var/log/nginx directory to the container's /var/log/nginx directory, and the other is an anonymous volume created by Docker at /var/lib/docker/volumes/... and mounted to the container's /etc/nginx/conf.d directory2.

'Mounts': [

{

'Type': 'bind',

'Source': '/var/log/nginx',

'Destination': '/var/log/nginx',

'Mode': 'rw',

'RW': true,

'Propagation': 'rprivate'

},

{

'Type': 'volume',

'Name': 'f6eb3dfdd57b7e632f6329a6d9bce75a1e8ffdf94498e5309c6c81a87832c28d',

'Source': '/var/lib/docker/volumes/f6eb3dfdd57b7e632f6329a6d9bce75a1e8ffdf94498e5309c6c81a87832c28d/_data',

'Destination': '/etc/nginx/conf.d',

'Driver': 'local',

'Mode': '',

'RW': true,

'Propagation': ''

}

]

docker container inspect

List volumes of Docker container