docker-practice/data/1_Orchestration/apply_node_labels_placement_tasks.yaml at v1.5 · efficience-it/docker-practice · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
questions:
  - uuid: 6cc6a97c-52dc-40c7-9cd3-7ef57709a38c
    question: What command adds a label to a Docker Swarm node?
    answers:
      - { value: 'docker service create --label', correct: false }
      - { value: 'docker node update --label-add', correct: true }
      - { value: 'docker swarm label add', correct: false }
      - { value: 'docker label node', correct: false }
    help: https://docs.docker.com/reference/cli/docker/node/update/

  - uuid: b0633cfc-51d0-4b00-a97f-0882b2689f08
    question: How can you inspect the labels of a node?
    answers:
      - { value: 'docker node list --labels', correct: false }
      - { value: 'docker inspect --labels', correct: false }
      - { value: 'docker node inspect <node> --pretty', correct: true }
      - { value: 'docker node info', correct: false }
    help: https://docs.docker.com/reference/cli/docker/node/inspect/

  - uuid: a372b99d-0e1e-4e58-80ed-818e948c0e30
    question: What placement constraint ensures a service runs only on nodes with a specific label?
    answers:
      - { value: '--require-label key=value', correct: false }
      - { value: '--constraint node.labels.key == value', correct: true }
      - { value: '--affinity key=value', correct: false }
      - { value: '--label key=value', correct: false }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: e187c71b-dbf3-4488-b1d5-009d5ff3a383
    question: What is the purpose of node labels in a Swarm cluster?
    answers:
      - { value: 'To enforce security policies', correct: false }
      - { value: 'To prioritize CPU resource allocation', correct: false }
      - { value: 'To identify the container logs per node', correct: false }
      - { value: 'To control where services are deployed using constraints', correct: true }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: c8db2350-5126-43f4-bf6b-dfddf71a3c15
    question: What happens if no node satisfies the placement constraint?
    answers:
      - { value: 'The service is deployed on all nodes', correct: false }
      - { value: 'The service is not deployed', correct: true }
      - { value: 'The service is ignored', correct: false }
      - { value: 'Docker overrides the constraint', correct: false }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: 63a88ed9-7ba3-4a9d-b0ae-76e54e6fa8a0
    question: How do you deploy a service to nodes labeled `env=production`?
    answers:
      - { value: 'docker node create --label env=production', correct: false }
      - { value: 'docker service create --constraint node.labels.env == production', correct: true }
      - { value: 'docker service create --label env=production', correct: false }
      - { value: 'docker run --env production', correct: false }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: b85fcb9d-9936-4a41-bc64-c54084ac0b36
    question: Can node labels be used to filter nodes when scaling services?
    answers:
      - { value: 'No, scaling ignores node labels', correct: false }
      - { value: 'Yes, placement constraints apply during scaling', correct: true }
      - { value: 'Only for global services', correct: false }
      - { value: 'Only for daemon sets', correct: false }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: 2a6e9114-8717-498e-8f65-7052ac28c3c6
    question: How do you remove a label from a node?
    answers:
      - { value: 'docker node update --label-rm <label>', correct: true }
      - { value: 'docker node label remove', correct: false }
      - { value: 'docker label rm', correct: false }
      - { value: 'docker node delete label', correct: false }
    help: https://docs.docker.com/reference/cli/docker/node/update/

  - uuid: 45fc67df-81be-4b4b-a96f-4de88ac5856f
    question: Can a service have multiple placement constraints?
    answers:
      - { value: 'Only if --mode=global', correct: false }
      - { value: 'Only with node affinity enabled', correct: false }
      - { value: 'No, only one is allowed', correct: false }
      - { value: 'Yes, use multiple --constraint flags', correct: true }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints
  - uuid: f08f5a14-376a-4f56-a5d5-6b9ed18f82c5
    question: Where are node labels stored in a Docker Swarm cluster?
    answers:
      - { value: 'In the image layer', correct: false }
      - { value: 'In the Raft log replicated across all managers', correct: true }
      - { value: "Only in the local node's filesystem", correct: false }
      - { value: 'In container metadata', correct: false }
    help: https://docs.docker.com/engine/swarm/how-swarm-mode-works/nodes/

  - uuid: 7a233b58-f90a-4692-bfa2-2466c86b6303
    question: What happens if a node with a required label is removed from the cluster?
    answers:
      - { value: 'The label is ignored and the task is rescheduled anywhere', correct: false }
      - { value: 'The service is stopped entirely', correct: false }
      - { value: 'The cluster auto-applies the label to another node', correct: false }
      - { value: 'Tasks using that constraint are rescheduled only if another node has the label', correct: true }
    help: https://docs.docker.com/engine/swarm/services/#placement-constraints

  - uuid: b2e91bbf-21fa-4fd9-8c83-e4a64676e750
    question: Which file can define placement constraints when using docker stack deploy?
    answers:
      - { value: 'swarm-config.json', correct: false }
      - { value: 'Dockerfile', correct: false }
      - { value: 'service.conf', correct: false }
      - { value: 'docker-compose.yml with deploy.placement.constraints', correct: true }
    help: https://docs.docker.com/compose/compose-file/compose-file-v3/#placement

  - uuid: 6eb90544-0bdf-49ea-b6ed-4fcad88fc7b7
    question: Which command shows all nodes with their labels?
    answers:
      - { value: 'docker service inspect --labels', correct: false }
      - { value: 'docker node show-labels', correct: false }
      - { value: 'docker inspect --type node', correct: false }
      - { value: 'docker node ls && docker node inspect <node>', correct: true }
    help: https://docs.docker.com/reference/cli/docker/node/inspect/