Deployments, ReplicaSets, and DaemonSets
As we saw in the previous chapter, there are more resources in Kubernetes than just Pods and namespaces. Let’s learn about Deployments, for starters.
Deployment
It is a wrapper for declarative updates for Pods and ReplicaSets. After you describe the desired state in the Deployment resource spec, the Kubernetes Deployment controller changes the current state to the desired state at a configured rate.
It sounds complicated, but essentially Deployment is for controlling Pods and managing the application life cycle of those Pods. Pods are the smallest deployment units that wrap around containers, but they don’t provide any advanced Kubernetes features, such as self-healing, rolling updates, or autoscaling. However, Deployments do.
Because Pods are not resilient, an application container that fails in a pod takes the pod down with it. That is why in practice you’ll often use one of the advanced Kubernetes resources...
