Updating an App in Kubernetes (K8s)

Users expect applications to be available all the time, and developers are expected to deploy new versions of them several times a day. In Kubernetes this is done with rolling updates. A rolling update allows a Deployment update to take place with zero downtime. It does this by incrementally replacing the current Pods with new ones. The new Pods are scheduled on Nodes with available resources, and Kubernetes waits for those new Pods to start before removing the old Pods.

Actions

Rolling updates allow the following actions:

Steps of rolling update

Step 1


Fig-01: Rolling Update Step 1

Step 2


Fig-02: Rolling Update Step 2

Step 3


Fig-03: Rolling Update Step 3

Step 4


Fig-04: Rolling Update Step 4