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Add new questions for Orchestration and Image Creation domains (#52)
Orchestration (+38 questions): - service_update_rollback.yaml: update/rollback strategies (10) - node_availability.yaml: drain/active/pause states (8) - swarm_autolock.yaml: autolock feature (6) - secrets_and_configs.yaml: Docker secrets and configs (8) - service_healthcheck.yaml: health checks in Swarm (6) Image Creation (+32 questions): - healthcheck_instruction.yaml: HEALTHCHECK in Dockerfile (6) - buildkit_buildx.yaml: BuildKit and buildx (6) - cmd_vs_entrypoint.yaml: CMD vs ENTRYPOINT deep dive (8) - arg_vs_env.yaml: ARG vs ENV instructions (6) - build_cache.yaml: build cache optimization (6)
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‎README.md‎

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@@ -41,6 +41,11 @@ The goal is to help candidates:
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* [Describe how a Dockerized application communicates with legacy systems.](data/1_Orchestration/legacy_communication.yaml)
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* [Describe how to deploy containerized workloads as Kubernetes pods and deployments.](data/1_Orchestration/k8s_pods_deployments.yaml)
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* [Describe how to provide configuration to Kubernetes pods using configMaps and secrets.](data/1_Orchestration/k8s_configmap_secret.yaml)
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* [Describe service update and rollback strategies.](data/1_Orchestration/service_update_rollback.yaml)
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* [Describe node availability (drain, active, pause).](data/1_Orchestration/node_availability.yaml)
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* [Describe the Swarm autolock feature.](data/1_Orchestration/swarm_autolock.yaml)
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* [Describe Docker secrets and configs in Swarm.](data/1_Orchestration/secrets_and_configs.yaml)
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* [Describe service health checks in Swarm.](data/1_Orchestration/service_healthcheck.yaml)
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### Domain 2: Image Creation, Management, and Registry (20% of exam)
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* [Push an image to a registry.](data/2_Image_creation_management_registry/push_an_image_to_a_registry.yaml)
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* [Sign an image in a registry.](data/2_Image_creation_management_registry/sign_an_image_in_a_registry.yaml)
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* [Pull and delete images from a registry.](data/2_Image_creation_management_registry/pull_delete_images_registry.yaml)
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* [Describe the HEALTHCHECK instruction in a Dockerfile.](data/2_Image_creation_management_registry/healthcheck_instruction.yaml)
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* [Describe BuildKit and docker buildx.](data/2_Image_creation_management_registry/buildkit_buildx.yaml)
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* [Compare CMD vs ENTRYPOINT instructions.](data/2_Image_creation_management_registry/cmd_vs_entrypoint.yaml)
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* [Compare ARG vs ENV instructions.](data/2_Image_creation_management_registry/arg_vs_env.yaml)
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* [Describe Docker build cache optimization.](data/2_Image_creation_management_registry/build_cache.yaml)
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### Domain 3: Installation and Configuration (15% of exam)
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‎data/1_Orchestration/node_availability.yaml‎

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questions:
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- uuid: 7427d279-6a03-499d-8db8-8b33f60ec85e
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question: Which command sets a Swarm node to drain availability?
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answers:
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- { value: 'docker node update --availability drain <node>', correct: true }
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- { value: 'docker node drain <node>', correct: false }
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- { value: 'docker swarm update --drain <node>', correct: false }
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- { value: 'docker node set --status drain <node>', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/node/update/'
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- uuid: f4a6b9b3-8933-4c9c-9ea1-d8345989ea76
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question: What happens to running tasks on a node when its availability is set to drain?
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answers:
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- { value: 'Tasks are paused until the node is set back to active', correct: false }
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- { value: 'Tasks are stopped and rescheduled on other available nodes', correct: true }
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- { value: 'Tasks continue running but no new tasks are assigned', correct: false }
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- { value: 'Tasks are deleted permanently', correct: false }
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help: 'https://docs.docker.com/engine/swarm/swarm-tutorial/drain-node/'
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- uuid: 6d2a3fc6-f24e-4252-8e6b-1a7917f91a6e
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question: What are the three possible availability states for a Docker Swarm node?
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answers:
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- { value: 'active, pause, drain', correct: true }
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- { value: 'running, stopped, paused', correct: false }
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- { value: 'active, inactive, drain', correct: false }
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- { value: 'ready, standby, offline', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/node/update/'
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- uuid: 70d6f4a7-8e5c-4b1d-a3f9-4c0e7d2b5a38
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question: What is the effect of setting a node to "pause" availability?
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answers:
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- { value: 'All running tasks are stopped immediately', correct: false }
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- { value: 'The node leaves the Swarm cluster', correct: false }
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- { value: 'The node does not receive new tasks but existing tasks continue running', correct: true }
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- { value: 'The node becomes a manager node', correct: false }
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help: 'https://docs.docker.com/engine/swarm/swarm-tutorial/drain-node/'
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- uuid: 81e7a5b8-9f6d-4c2e-b4a0-5d1f8e3c6b49
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question: Can a manager node be drained in Docker Swarm?
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answers:
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- { value: 'No, manager nodes cannot be drained', correct: false }
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- { value: 'Yes, but it loses its manager status', correct: false }
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- { value: 'Yes, it stops running tasks but retains its manager role', correct: true }
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- { value: 'Yes, but only if there is a single manager in the cluster', correct: false }
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help: 'https://docs.docker.com/engine/swarm/swarm-tutorial/drain-node/'
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- uuid: 71b27922-45ab-4e23-822e-692c78185b05
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question: After draining a node and performing maintenance, which command makes the node available for tasks again?
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answers:
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- { value: 'docker node update --availability active <node>', correct: true }
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- { value: 'docker node activate <node>', correct: false }
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- { value: 'docker node update --status ready <node>', correct: false }
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- { value: 'docker node resume <node>', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/node/update/'
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- uuid: cde811d8-6da1-4771-8737-849ef4fab487
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question: When a drained node is set back to active, do previously running tasks automatically move back to it?
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answers:
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- { value: 'Yes, all tasks return to their original node', correct: false }
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- { value: 'Yes, but only global service tasks return', correct: false }
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- { value: 'No, existing tasks stay where they are; the node only receives new or rebalanced tasks', correct: true }
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- { value: 'No, the node must rejoin the Swarm to receive tasks', correct: false }
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help: 'https://docs.docker.com/engine/swarm/swarm-tutorial/drain-node/'
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- uuid: f19b3d4c-c3dd-433a-9f25-3ec41f55aba0
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question: Which command can you use to verify the current availability status of all Swarm nodes?
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answers:
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- { value: 'docker swarm status', correct: false }
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- { value: 'docker node ls', correct: true }
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- { value: 'docker info --nodes', correct: false }
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- { value: 'docker service ps --all', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/node/ls/'

‎data/1_Orchestration/secrets_and_configs.yaml‎

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questions:
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- uuid: f5adb06a-f283-4072-8330-e8a12a751a4e
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question: Which command creates a Docker secret from a file?
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answers:
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- { value: 'docker secret add my_secret ./secret.txt', correct: false }
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- { value: 'docker secret create my_secret ./secret.txt', correct: true }
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- { value: 'docker service secret --add my_secret ./secret.txt', correct: false }
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- { value: 'docker config create --secret my_secret ./secret.txt', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/secret/create/'
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- uuid: d2d8f6a9-0e7b-4b3c-a5f1-6c2e9d4b7a50
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question: Where are Docker secrets mounted inside a service container by default?
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answers:
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- { value: '/etc/secrets/<secret_name>', correct: false }
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- { value: '/var/run/secrets/<secret_name>', correct: false }
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- { value: '/run/secrets/<secret_name>', correct: true }
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- { value: '/tmp/secrets/<secret_name>', correct: false }
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help: 'https://docs.docker.com/engine/swarm/secrets/#how-docker-manages-secrets'
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- uuid: e3e9a7b0-1f8c-4c4d-b6a2-7d3f0e5c8b61
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question: Which command creates a Docker config from a file?
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answers:
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- { value: 'docker config create my_config ./config.txt', correct: true }
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- { value: 'docker config add my_config ./config.txt', correct: false }
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- { value: 'docker service config --add my_config ./config.txt', correct: false }
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- { value: 'docker create config my_config ./config.txt', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/config/create/'
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- uuid: 17a35533-1048-467a-bf3f-3cf2511e60a5
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question: What is a key difference between Docker secrets and Docker configs?
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answers:
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- { value: 'Secrets are stored in Raft log encrypted; configs are not encrypted at rest', correct: true }
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- { value: 'Configs can only be used with global services', correct: false }
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- { value: 'Secrets are mounted as volumes; configs are set as environment variables', correct: false }
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- { value: 'Configs are limited to 100KB; secrets have no size limit', correct: false }
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help: 'https://docs.docker.com/engine/swarm/configs/'
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- uuid: 62f66a6c-b332-4f77-ba3f-f0bc8417c8ab
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question: How do you grant a running service access to an existing secret?
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answers:
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- { value: 'docker secret attach my_secret myservice', correct: false }
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- { value: 'docker service update --secret-add my_secret myservice', correct: true }
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- { value: 'docker service update --mount secret=my_secret myservice', correct: false }
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- { value: 'docker secret grant my_secret myservice', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/update/'
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- uuid: fe43e84a-19ae-40e3-83f1-8e0c89d627cc
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question: Can you update or change the content of an existing Docker secret?
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answers:
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- { value: 'Yes, using docker secret update', correct: false }
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- { value: 'Yes, by overwriting it with docker secret create --force', correct: false }
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- { value: 'No, secrets are immutable; you must create a new secret and update the service', correct: true }
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- { value: 'Yes, but only if no service is using it', correct: false }
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help: 'https://docs.docker.com/engine/swarm/secrets/#example-rotate-a-secret'
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- uuid: c59fa65c-9ee6-4989-95c0-4b4e45148d8a
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question: Where are Docker configs mounted inside a container by default?
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answers:
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- { value: '/run/configs/<config_name>', correct: false }
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- { value: '/<config_name>', correct: true }
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- { value: '/etc/configs/<config_name>', correct: false }
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- { value: '/var/config/<config_name>', correct: false }
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help: 'https://docs.docker.com/engine/swarm/configs/#how-docker-manages-configs'
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- uuid: d8d4f2a5-6e3b-4b9c-a1f7-2c8e5d0a3b16
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question: Which Docker feature requires Swarm mode to function?
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answers:
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- { value: 'Volumes', correct: false }
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- { value: 'Bridge networks', correct: false }
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- { value: 'Secrets', correct: true }
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- { value: 'Bind mounts', correct: false }
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help: 'https://docs.docker.com/engine/swarm/secrets/'

‎data/1_Orchestration/service_healthcheck.yaml‎

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questions:
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- uuid: e9e5a3b6-7f4d-4c0e-b2a8-3d9f6e1b4c27
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question: Which flag defines a health check command when creating a Docker Swarm service?
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answers:
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- { value: '--health-test', correct: false }
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- { value: '--healthcheck', correct: false }
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- { value: '--health-cmd', correct: true }
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- { value: '--check-health', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/create/#health-cmd'
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- uuid: 44213b9c-edb1-490e-b6d7-8b83c6e61051
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question: What are the three possible health states of a container with a health check configured?
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answers:
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- { value: 'healthy, unhealthy, unknown', correct: false }
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- { value: 'starting, healthy, unhealthy', correct: true }
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- { value: 'running, stopped, failed', correct: false }
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- { value: 'passing, warning, critical', correct: false }
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help: 'https://docs.docker.com/reference/dockerfile/#healthcheck'
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- uuid: 780e95d2-b8f5-428e-9ed7-2b2cd01147d7
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question: What does the --health-retries flag specify?
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answers:
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- { value: 'The number of times to retry a failed service deployment', correct: false }
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- { value: 'The number of consecutive health check failures needed to report unhealthy', correct: true }
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- { value: 'The number of health checks to run in parallel', correct: false }
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- { value: 'The number of nodes to check health on', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/create/#health-retries'
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- uuid: 7ca92d5f-1075-4c7e-af6a-3ade80273bd3
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question: What does the --health-start-period flag control?
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answers:
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- { value: 'The time to wait before the first health check runs', correct: false }
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- { value: 'The grace period during which health check failures are not counted toward the maximum retries', correct: true }
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- { value: 'The interval between health checks at service startup', correct: false }
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- { value: 'The maximum time allowed for the service to start', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/create/#health-start-period'
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- uuid: 96f70b46-c101-4d79-a032-d0fd10dc4297
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question: What happens to a Swarm service task when its container is reported as unhealthy?
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answers:
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- { value: 'The task is paused and an alert is sent', correct: false }
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- { value: 'Nothing happens; the task continues running', correct: false }
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- { value: 'The task is stopped and a new task is scheduled to replace it', correct: true }
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- { value: 'The task is moved to a different node', correct: false }
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help: 'https://docs.docker.com/engine/swarm/how-swarm-mode-works/services/'
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- uuid: d4d0f8a1-2e9c-4b5d-a7f3-8c4e1d6a9b72
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question: What is the default interval between health checks if --health-interval is not specified?
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answers:
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- { value: '10s', correct: false }
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- { value: '30s', correct: true }
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- { value: '1m', correct: false }
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- { value: '5s', correct: false }
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help: 'https://docs.docker.com/reference/dockerfile/#healthcheck'

‎data/1_Orchestration/service_update_rollback.yaml‎

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questions:
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- uuid: a3c7e1b4-9f2d-4e8a-b5c6-1d3f7a9e2b04
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question: Which command updates the image of an existing Docker Swarm service named "web" to nginx:1.25?
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answers:
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- { value: 'docker service update --image nginx:1.25 web', correct: true }
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- { value: 'docker service create --image nginx:1.25 web', correct: false }
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- { value: 'docker service scale --image nginx:1.25 web', correct: false }
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- { value: 'docker update --image nginx:1.25 web', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/update/'
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- uuid: b8d4f2a5-6e3c-4b9d-a1f7-2c8e5d0a3b16
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question: What does the --update-delay flag control during a service update?
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answers:
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- { value: 'The time to wait before starting the update', correct: false }
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- { value: 'The time to wait between updating each group of tasks', correct: true }
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- { value: 'The maximum time a single task update can take', correct: false }
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- { value: 'The time to wait before rolling back on failure', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: c9e5a3b6-7f4d-4c0e-b2a8-3d9f6e1b4c27
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question: What does --update-parallelism 3 mean when updating a service?
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answers:
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- { value: 'Three services are updated at the same time', correct: false }
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- { value: 'The update runs on three nodes simultaneously', correct: false }
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- { value: 'Three tasks are updated at a time during the rolling update', correct: true }
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- { value: 'The update retries three times on failure', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 39b5ce22-cbe0-465e-a39a-551f9775a62c
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question: What is the default value for --update-failure-action in Docker Swarm?
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answers:
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- { value: 'rollback', correct: false }
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- { value: 'continue', correct: false }
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- { value: 'pause', correct: true }
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- { value: 'stop', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 216987ff-de4a-44e0-a854-38d136f311e9
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question: Which command manually triggers a rollback of a Docker Swarm service?
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answers:
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- { value: 'docker service revert myservice', correct: false }
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- { value: 'docker service update --undo myservice', correct: false }
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- { value: 'docker service rollback myservice', correct: true }
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- { value: 'docker service update --previous myservice', correct: false }
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help: 'https://docs.docker.com/reference/cli/docker/service/rollback/'
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- uuid: 42faf48b-afa1-46cd-b294-27d1b86f26ae
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question: What does the --update-order start-first option do during a service update?
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answers:
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- { value: 'It starts the new task before stopping the old task', correct: true }
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- { value: 'It stops the old task before starting the new task', correct: false }
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- { value: 'It starts the update on the first node in the cluster', correct: false }
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- { value: 'It prioritizes manager nodes during the update', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 9c3cb4aa-daa3-4e0a-b80b-9ae8757d2ee6
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question: What is the default update order for Docker Swarm service updates?
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answers:
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- { value: 'start-first', correct: false }
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- { value: 'stop-first', correct: true }
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- { value: 'parallel', correct: false }
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- { value: 'round-robin', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 14d0f8a1-2e9c-4b5d-a7f3-8c4e1d6a9b72
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question: Which flag sets the maximum time a single task has to update before it is considered failed?
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answers:
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- { value: '--update-delay', correct: false }
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- { value: '--update-timeout', correct: false }
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- { value: '--update-monitor', correct: true }
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- { value: '--update-max-time', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 25e1a9b2-3f0d-4c6e-b8a4-9d5f2e7b0c83
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question: How do you configure a service so that it automatically rolls back if an update fails?
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answers:
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- { value: '--update-failure-action rollback', correct: true }
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- { value: '--rollback-on-failure true', correct: false }
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- { value: '--update-auto-rollback', correct: false }
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- { value: '--update-failure-action revert', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#configure-a-services-update-behavior'
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- uuid: 372fc663-77c2-4bcf-aa95-cc365ffac6f0
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question: Which flag configures the delay between task rollbacks during an automatic rollback?
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answers:
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- { value: '--update-delay', correct: false }
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- { value: '--rollback-delay', correct: true }
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- { value: '--rollback-interval', correct: false }
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- { value: '--rollback-wait', correct: false }
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help: 'https://docs.docker.com/engine/swarm/services/#roll-back-to-the-previous-version-of-a-service'

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