func (c *Resources) requiredInstances(cluster core.ClusterInterface, service framework.ServiceConfig) (int, error) {
requiredInstances := 0
deployedService, err := cluster.FindService(service.Namespace, service.ServiceName, service.CompatibilityVersion)
if err != nil {
return 0, err
}
if deployedService == nil {
requiredInstances = service.Instances
logger.Instance().Infof("The service is new in cluster %s, deploy needs resources for %d instances", cluster.Id(), requiredInstances)
} else if len(deployedService.Instances) == service.Instances {
requiredInstances = int(math.Max(1, math.Floor(float64(service.Instances)*0.2)))
logger.Instance().Infof("Service replacement in cluster %s, deploy needs resources for %d instances", cluster.Id(), requiredInstances)
} else if len(deployedService.Instances) < service.Instances {
requiredInstances = service.Instances - len(deployedService.Instances)
logger.Instance().Infof("Service up scale in cluster %s, deploy needs resources for %d instances", cluster.Id(), requiredInstances)
} else {
logger.Instance().Infof("Service down scale in cluster %s, the cluster should have enough resources", cluster.Id())
}
return requiredInstances, nil
}
