Rolling Upgrade

You are advised to use ServiceStage to deploy Java chassis applications, which facilitates rolling upgrade.

When using ServiceStage to deploy applications, you can configure component service probes so that ServiceStage can correctly detect microservice statuses. To configure the component service probe, you need to enable the metrics function and set the component service probe path to /health.

<dependency>
  <groupId>org.apache.servicecomb</groupId>
  <artifactId>metrics-core</artifactId>
</dependency>

In addition to setting probes, you need to set the rolling upgrade policy. The core parameters include the Max. Unavailable Pods. The default values of these two parameters are both 0. If there is only one instance, the rolling upgrade will be interrupted. You are advised to set Max. Unavailable Pods ≥ 2, 0 ≤ Max. Unavailable Pods < Pods–1. That is, at least 2 instances are available.