GKE自动缩放不会缩小

Cloud Composer does not yet (as of 2019/08/26) support the GKE cluster autoscaler, because the cluster autoscaler makes scaling decisions based on the resource requests of Pods, as well as how many Pods are in the unschedulable state (more information here). Composer deploys a fixed number of Pods, which means the autoscaling mechanism doesn't force any scaling action unless you yourself are deploying your own workloads into the cluster.

自动缩放也很困难，因为Airflow工作人员或调度程序的实际资源使用情况取决于您上传的DAG数（在Composer中为GCS），这意味着无法准确估算您的Airflow进程将使用多少CPU /内存。 。这意味着您不知道如何确定Airflow Pod的Pod资源请求。

在没有自动缩放的情况下，动态资源分配仍然有很多选择。例如，你可以使用KubernetesPodOperator与资源请求到部署荚不同的是Kubernetes集群并有自动缩放功能。另外，您可以使用GCE运算符将实例添加到群集中，然后再启动更多占用大量资源的工作负载。