QUESTION: 33

Does this command create a swarm service that only listens on port 53 using the UDP protocol?

Solution: 'docker service create --name dns-cache -p 53:53/udp dns-cache'

Yes
No

Answer(s): A

Explanation:

= The command `docker service create --name dns-cache -p 53:53/udp dns-cache' creates a swarm service that only listens on port 53 using the UDP protocol. This is because the -p flag specifies the port mapping between the host and the service, and the /udp suffix indicates the protocol to use. Port 53 is commonly used for DNS services, which use UDP as the default transport protocol. The dns-cache argument is the name of the image to use for the service.

Reference:

docker service create | Docker Documentation

DNS - Wikipedia

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

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QUESTION: 34

Does this command create a swarm service that only listens on port 53 using the UDP protocol?

Solution: `docker service create -name dns-cache -p 53:53 -service udp dns-cache'

Yes
No

Answer(s): B

Explanation:

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.

Reference:

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

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QUESTION: 35

You want to provide a configuration file to a container at runtime. Does this set of Kubernetes tools and steps accomplish this?

Solution: Turn the configuration file into a configMap object and mount it directly into the appropriate pod and container using the .spec.containers.configMounts key.

Yes
No

Answer(s): B

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QUESTION: 36

You want to provide a configuration file to a container at runtime. Does this set of Kubernetes tools and steps accomplish this?

Solution: Mount the configuration file directly into the appropriate pod and container using the .spec.containers.configMounts key.

Yes
No

Answer(s): B

Explanation:

The solution given is not a valid way to provide a configuration file to a container at runtime using Kubernetes tools and steps. The reason is that there is no such key as .spec.containers.configMounts in the PodSpec. The correct key to use is .spec.containers.volumeMounts, which specifies the volumes to mount into the container's filesystem. To use a ConfigMap as a volume source, one needs to create a ConfigMap object that contains the configuration file as a key-value pair, and then reference it in the .spec.volumes section of the PodSpec. A ConfigMap is a Kubernetes API object that lets you store configuration data for other objects to use. For example, to provide a nginx.conf file to a nginx container, one can do the following steps:

Create a ConfigMap from the nginx.conf file:

kubectl create configmap nginx-config --from-file=nginx.conf

Create a Pod that mounts the ConfigMap as a volume and uses it as the configuration file for the nginx container:

apiVersion: v1

kind: Pod metadata:

name: nginx-pod spec:

containers:

- name: nginx image: nginx volumeMounts:

- name: config-volume mountPath: /etc/nginx/nginx.conf subPath: nginx.conf volumes:

- name: config-volume configMap:

name: nginx-config

Reference:

Configure a Pod to Use a Volume for Storage | Kubernetes

Configure a Pod to Use a ConfigMap | Kubernetes

ConfigMaps | Kubernetes

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QUESTION: 33

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QUESTION: 34

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QUESTION: 35

QUESTION: 36

Explanation:

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