How Kubernetes Deployment Work | Kubernetes Deployment Tutorial | Ntirawen

What is Kubernetes ?

• Open Source and portable platform
• Automates scaling of workloads
• Groups containers into logical units
• Google's Brainchild. Now, donated to CNCF
• Written in Go programming language
• A container orchestration tool

What is a Pod ?

Pod is the basic unit of Kubernetes. A pod can consist of one or more container images.

Is widely used when a container runs on a physical machine on top of an operating system.

Used for applications which are dependent on other applications/services for their functioning.

Replication Controller :

Replication Controller is one of the key features of Kubernetes, and is responsible for managing the pod lifecycle. It owns the responsibility for making sure that the specified number of pod replicas are running at any given point of time.

ReplicaSets :

ReplicaSet ensures how many replica of pod should be running. It can be considered as a replacement of replication controller.

Deployment Controllers :

Deployment Controller are declarative in nature to provide the required information / updates to pod and ReplicaSets. Deployment Controller changes the actual state of the defined desired state of controller object.

Deployment Use - Cases 

Create a Deployment ➝ A deployment is created. Once that is done the ReplicaSet automatically creates Pods in the background.

Update Deployment ➝ A new ReplicaSet is created and the Deployment is updated. Each new ReplicSet updates the revision of Deployment.

Rollback Deployment ➝ Used in case when the current state of the deployment is not stable. Only the container image gets updated.

Scale a Deployment ➝ Each and every deployment can be scaled up or scaled down based on the requirement.

Pause the Deployment ➝ Pause the deployment to apply multiple fixes and then the deployment can be resumed.