How does the Pod update in a Deployment work — what is it implemented through?

Pod updates in Deployment are implemented through the Rolling Update mechanism, which is managed by the Deployment controller in Kubernetes. The controller gradually creates new Pods with the updated configuration and simultaneously deletes the old ones, maintaining the specified number of replicas.

Main steps:

• A ReplicaSet with the new version of Pods is created.
• The number of new Pods gradually increases while the number of old Pods decreases.
• The update occurs in stages to avoid downtime.
• If errors occur, the update can be paused or rolled back.

This is achieved through comparing Pod templates and managing ReplicaSets, ensuring a smooth and controlled transition to the new application version.