You can run the following command to add nodes to a node pool: arc-cs nodepools scaleout <cluster_id> <nodepool_id> --count <instance_scaleout_number>.

Notice This command is applicable to only custom node pools.

For more information about this command, see ScaleClusterNodePool.

Example by using Alibaba Cloud CLI

Sample request:
arc-cs nodepool scaleout caa73d115830746e0942c9554ecae**** npd4cc395c77ee467b9c68db3cabed**** \
--count 1
Sample response:
  "taskId": "T-60190e374d345a4821000052"