update kubernetes deployment with jenkins
This is expected behavior. Every time you update a Deployment a new ReplicaSet will be created. But, old ReplicaSet will be kept so that you can roll-back to previous state in case of any problem in your updated Deployment.
However, you can limit how many ReplicaSet should be kept through spec.revisionHistoryLimit
field. Default value is 10. Ref: RevisionHistoryLimit