With the introduction of public and private cloud solutions such as AWS and OpenStack, there has been a shift towards utilizing immutable infrastructure instead of traditional static servers.
This has raised a point of contention with pets versus cattle or, as Gartner defines it bi-modal (http://www.gartner.com/it-glossary/bimodal/).
Gartner has said that two different strategies need to be adopted, one for new microservices, cattle, and one for legacy infrastructure, pets. Cattle are servers that are killed off once they have served their purpose or have an issue, typically lasting one release iteration. Alternately, pets are servers that will have months or years of uptime and will be patched and cared for by operations staff.
Gartner defines pets as Mode 1 and cattle as Mode 2. It is said that a cattle approach favors the stateless microservice cloud-native applications, whereas a pet, on the other hand, is any application that is a monolith...