How does 'kubectl apply -f' update a deployment behind the scenes?

Question

I have a deployment created with a YAML file, the image for the containers is image:v1.

Now I update the file to image:v2, and do kubectl apply -f newDeploymentFile.yml. Does Kubernetes use rolling update behind the scenes to update my deployment or some other way?

Answer 1

What happens exactly is controlled by the Deployment itself:

• .spec.stategy: RollingUpdate (default) or Recreate
• .spec.strategy.rollingUpdate: see the docs I've linked for the explanation of the maxSurge and maxUnavailable

(I assumed that by deployment you actually mean a Deployment type object and not speaking in general.)