They are all named after deserts.
Naming stuff after a specific subject is very common in the IT industry. Many people name servers after cosmic stuff or Greek Mythology.
If you notice, Intel names most of their projects after towns, rivers or mountains close by.
Google chose deserts for Android.
I used to do it for my servers, but quit a some years ago. When you get so many servers and the mix and matching of services running on those servers, it become impractical. Naming releases is much easier.
Today I just use a location / service ID scheme I created. The tag tells me where it is and what it is doing and which of that group of servers it is.