Here is a photograph of my ESG colleague Taya Wyss and Cesar Orosco from NetApp in Sunnyvale standing in a smart cold aisle containment system. This is an aftermarket fitting in a relatively old data centre but nevertheless a useful improvement to cooling efficiency.
The photograph shows cabinets facing front to front so that the air can be drawn out of the cold aisle and exhausted into the rest of the data centre. You can see the plastic roof on the top of the cabinets and the door at the end of the aisle. You can also see some very neat (cheap and effective) blanking plates that are used to reduce the ability for air to short circuit past the servers.