Performing a Rolling Update

    • Perform a rolling update using kubectl.

    In the previous module we scaled our application to run multiple instances. This is a requirement for performing updates without affecting application availability. By default, the maximum number of Pods that can be unavailable during the update and the maximum number of new Pods that can be created, is one. Both options can be configured to either numbers or percentages (of Pods). In Kubernetes, updates are versioned and any Deployment update can be reverted to a previous (stable) version.

    Rolling updates allow Deployments’ update to take place with zero downtime by incrementally updating Pods instances with new ones.

    Performing a Rolling Update - 图3

    Next

    Rolling updates allow the following actions:

    • Promote an application from one environment to another (via container image updates)
    • Rollback to previous versions

    If a Deployment is exposed publicly, the Service will load-balance the traffic only to available Pods during the update.

    In the following interactive tutorial, we’ll update our application to a new version, and also perform a rollback.