DCA Exam Dumps : Docker Certified Associate (DCA) Exam

= The ‘docker inspect’ command returns low-level information on Docker objects, such as containers, images, networks, etc1 It does not show the list of historical tasks for a service. To view the list of tasks for a service, you need to use the ‘docker service ps’ command 2. For example, to see the tasks for the ‘http’ service, you would run ‘docker service ps http’. This would show the ID, name, image, node, desired state, current state, and error of each task 2. References: Docker inspect | Docker Docs, Docker service ps | Docker Docs

Node taints are a way to mark nodes in a Swarm cluster so that they can repel or attract certain containers based on their tolerations. By applying node taints to the nodes that are designated for development or production, the company can ensure that only the containers that have the matching tolerations can be scheduled on those nodes. This way, the security policy requirements can be met. Node taints are expressed as key=value:effect, where the effect can be NoSchedule, PreferNoSchedule, or NoExecute. For example, to taint a node for development only, one can run:

kubectl taint nodes node1 env=dev:NoSchedule

This means that no container will be able to schedule onto node1 unless it has a toleration for the taint env=dev:NoSchedule. To add a toleration to a container, one can specify it in the PodSpec. For example:

tolerations:

- key: "env"

operator: "Equal"

value: "dev"

effect: "NoSchedule"

This toleration matches the taint on node1 and allows the container to be scheduled on it. References:

Taints and Tolerations | Kubernetes

Update the taints on one or more nodes in Kubernetes

A Complete Guide to Kubernetes Taints & Tolerations

The statement is incorrect about the health check definition based on the Docker Compose file provided. According to the Docker documentation, a health check can be specified in a Dockerfile or a Docker Compose file to tell Docker how to test a container to check that it is still working. This can be done with options such asinterval,timeout, andretries. In this case, the health checks are not set to test five seconds apart but rather ten seconds apart (interval: 10s).Theretries: 3indicates that if the health check fails, Docker will try three times before considering the container unhealthy1.