Final answer:
The correct docker command to add or update a node label in Docker Swarm is either 'docker node update --label-add' to add a label, or 'docker node update --label-rm' to remove a label, followed by the key=value pair and the node ID.
Step-by-step explanation:
The docker command to add or update a node label is C) docker node update --label-add or docker node update --label-rm. When working with Docker Swarm, labeling nodes can help you control the placement of containers based on the labels you assign to each node. To add or update a label, you would use a command like:
docker node update --label-add
key=
value NODE_ID
Similarly, to remove a label from a node, you would use:
docker node update --label-rm
key NODE_ID
Replace key with the label name, value with the label value you want to set, and NODE_ID with the ID of the node you wish to update. This allows you to categorize your nodes for better resource allocation and management within a Docker Swarm cluster.
The correct question is: What is the docker command to add or update a node label?
A) docker node set-label
B) docker label add
C) docker node update --label
D) docker add-label