Configure Rolling Update

This articles will guide you how to configure rolling update for your service.

Before you begin

You need to understand the following concepts:

Gradual Deployment

1. Configure deployment manifest

Configure rolling update with Kubernetes is pretty straight forward, we just need to configure strategy to rollingUpdate in the deployment manifest.

...
  strategy:
    rollingUpdate:
      maxSurge: xx
      maxUnavailable: xx
...

maxUnavailable is an optional field to specify maximum number of pods that can be unavailable during the roll out process. The value can be percentage and absolute number. Default value is 25%.

maxSurge is an optional field to specify maximum number of pods that can be created above the original number of pods. The value can be percentage and absolute number. Default value is 25%.

These parameters can be tuned for availability and speed. For example:

maxUnavailable=0 and maxSurge=20% ensure number of pods is running as desired and rapid scale up
maxUnavailable=10% and maxSurge=0 performs update with no extra capacity
maxUnavailable=10% and maxSurge=10% scales up and down quickly, but the number of running pods might be lower than desired