To stop a CSS cluster, you delete it. If you want to stop a cluster upon completion of a cluster migration, stop all services in the source cluster, and confirm that all data has been migrated to the destination cluster. Then delete the source cluster. You can stop services in the source cluster in the following ways:
PUT log*/_settings
{
"index.blocks.read": true,
"index.blocks.write": true,
"index.blocks.metadata": true
}