Kubernetes Objects

Question 1

An API object that manages external access to the services in a cluster, typically HTTP.

Answer 1

Ingress Object.
Created with kubectl apply -f

Documentation here: https://kubernetes.io/docs/concepts/services-networking/ingress/

Question 2

Lets you do declarative updates to ReplicaSets and Pods.

Answer 2

Deployments. You describe a desired state in a Deployment, and the Deployment Controller changes the actual state to the desired state at a controlled rate. You can define Deployments to create new ReplicaSets, or to remove existing Deployments and adopt all their resources with new Deployments.

Question 3

Creates one or more Pods required to run a task. When complete, is terminated.

Answer 3

The Job controller creates one or more Pods required to run a task. When the task is completed, Job will then terminate all those Pods. A related controller is CronJob, which runs Pods on a time-based schedule.

Question 4

Ensures a specific number of Pods exist.

Answer 4

ReplicaSet.

A ReplicaSet’s purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods. A Deployment is a higher-level concept that manages ReplicaSets and provides declarative updates to Pods along with a lot of other useful features. Therefore, it is recommended you use Deployments instead of directly using ReplicaSets, unless you require custom update orchestration or don’t require updates at all.

https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/

Question 5

Is similar to a Deployment in that the Pods use the same container spec, but with a personal identity.

Answer 5

StatefulSet.

StatefulSets are valuable for:
    Stable, unique network identifiers.
    Stable, persistent storage.
    Ordered, graceful deployment and scaling.
    Ordered, automated rolling updates.

https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/