Overcloud deployment timed out when Compute nodes have many instances

Issue

• Updating overcloud by openstack overcloud deploy command failed due to timeout

  $ time openstack overcloud deploy ...
  
    :
  
  END return value: 1
  
  Overcloud Endpoint: http://10.0.0.1:5000
  Overcloud Horizon Dashboard URL: http://10.0.0.1:80/dashboard
  Overcloud rc file: /home/stack/overcloudrc
  Overcloud Deployed with error
  
  real  240m3.853s
  user  2m1.281s
  sys   0m4.814s
  

• Every ansible task takes long time, not a specific task.

• Overcloud hosts many instances.