A DevOps team is managing a Docker Swarm cluster with three manager nodes. During a network partition, one manager becomes isolated, while the other two remain connected and form a majority. What is the state of the isolated manager's Raft log and the overall cluster state?
A developer needs to provide a large, read-only dataset (2GB) to a service running on Docker Swarm. This dataset is updated nightly. To optimize for performance and storage, the team wants to avoid copying the data into each container's writable layer. Which volume mount type should be used when creating the service?
You are tasked with securing a Docker environment and want to prevent privilege-escalation attacks. Which of the following actions are considered best practices for achieving this? (Select TWO).
A financial services company is deploying a multi-service application on Kubernetes within a Docker Enterprise environment. A `backend-api` service needs to access a database whose credentials are changed quarterly for compliance. The credentials must not be stored in the container image or in version control. How should the database credentials be provided to the `backend-api` pods in a secure and manageable way?
A new service `webapp` needs to communicate with a `database` service, but it must be completely isolated from all other services and external traffic. Both services will be deployed on the same Docker overlay network. Which sequence of commands correctly sets up this isolated communication?
True or False: When using a multi-stage Dockerfile, artifacts from a previous stage can only be copied into a later stage using the `COPY --from= ` instruction; the `ADD` instruction cannot be used for this purpose.
A system administrator is configuring a new Docker host and wants to ensure that all containers, by default, have their logs sent to a central Splunk server. Where must this configuration be applied to be effective for all newly created containers on the host?
A development team is building a Go application. The build process requires several build-time dependencies and produces a single static binary. The final production image should be as small as possible and contain only the binary and its necessary OS certificates. Which Dockerfile instruction is essential for achieving this goal efficiently?
An administrator needs to perform maintenance on a specific worker node in a Docker Swarm cluster. To prevent the scheduler from placing any new tasks on this node, and to safely drain the existing tasks, which command should be used?
A developer is troubleshooting a container that fails to start. The command `docker logs ` produces no output. The container is running a custom application that is supposed to log to standard output. What is the most likely reason for the empty logs?