Deployment
A Deployment is a K8s object that oversees a group of identical pods, ensuring that a certain number of replicas are always running. It offers a declarative method for managing Kubernetes objects, enabling automated rollouts and rollbacks of containerized applications.
Additionally, a Deployment handles the deployment of new application versions and facilitates rollbacks to previous versions by creating and updating a ReplicaSet with the new configuration. A ReplicaSet maintains the desired number of pod replicas, creating new ones if any fail to ensure the desired state is preserved.
ReplicaSet
A ReplicaSet is a K8s object that ensures a specified number of pod replicas are running continuously. It oversees the lifecycle of pods, offering a way to scale and maintain the desired state of an application.
The ReplicaSet manages the creation and maintenance of pods based on a provided template specification. It generates new pod replicas as needed and removes outdated ones when they are no longer required. Additionally, it facilitates rolling updates and rollbacks by creating new replicas with updated configurations and terminating the old ones.
The difference
Deployment and ReplicaSet are tools used to manage the lifecycle of pods in Kubernetes. Deployment offers higher-level abstractions and advanced features like rolling updates, rollbacks, and application versioning. ReplicaSet, on the other hand, is a lower-level abstraction that provides fundamental scaling capabilities. When deciding between Deployment and ReplicaSet, consider the level of control and the features your application needs.