Kubernetes Deployments

Container application deployments within Kubernetes are done through Deployment resources. Deployment resources employ ReplicaSet resources behind the scenes, so it would be good to look at ReplicaSet resources first before we move on to understand Deployment resources.

ReplicaSet resource

ReplicaSet resources are Kubernetes resources that help you run multiple replicas of a Pod at a given time. They provide horizontal scaling for your container workloads, and it forms the basic building block of a horizontal scale set for your containers, which is a group of similar containers tied together to run as a unit.

ReplicaSet resources define the number of replicas of a Pod to run at a given time. The Kubernetes controller then tries to maintain the replicas and recreates a Pod if it goes down.

You should never use ReplicaSet resources on its own, but instead, it should act as a backend to a Deployment resource.

For the sake of understanding, however...