amazon-web-services - 在 2 个或更多实例之间添加 "cooldown"或 "pausetime"句点，同时减少所需容量

Question

(提前抱歉，因为我是 AWS 新手)。

我正在使用 cloudformation 堆栈来管理我的 ECS 集群。

假设我们有一个 ASG，其所需容量为 5 个 ec2 实例(minSize:1，maxSize:7)，并且我手动将所需容量的值从 5 更改为 2，它减少了通过集群更改集的实例数量，所有实例都会立即关闭。它没有时间分派(dispatch)回左侧实例上的前一个容器。因此，如果实例从 5 个变为 2 个，则所有 3 个实例都会直接关闭。如果运气不好，一种类型的所有容器都在 3 台机器上，则不再存在容器，服务就会关闭。

每次终止之间是否可以有一个“冷却时间”？使用扩展策略显然不会有帮助，因为我们不想设置指标，因为可用指标对我的情况没有帮助。

请在下面找到一些日志:

2021-01-15 15:45:52 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Rolling update initiated. Terminating 3 obsolete instance(s) in batches of 1, while keeping at least 1 instance(s) in service. Waiting on resource signals with a timeout of PT5M when new instances are added to the autoscaling group.
2021-01-15 15:45:52 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Temporarily setting autoscaling group MinSize and DesiredCapacity to 3.
2021-01-15 15:45:54 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Terminating instance(s) [i-X]; replacing with 1 new instance(s).
2021-01-15 15:47:40 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  New instance(s) added to autoscaling group - Waiting on 1 resource signal(s) with a timeout of PT5M.
2021-01-15 15:47:40 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Successfully terminated instance(s) [i-X] (Progress 33%).
2021-01-15 15:52:42 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Terminating instance(s) [i-X]; replacing with 1 new instance(s).
2021-01-15 15:53:59 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  New instance(s) added to autoscaling group - Waiting on 1 resource signal(s) with a timeout of PT5M.
2021-01-15 15:53:59 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Successfully terminated instance(s) [i-X] (Progress 67%).
2021-01-15 15:59:02 UTC+0100    dev-cluster UPDATE_ROLLBACK_IN_PROGRESS The following resource(s) failed to update: [autoScalingGroup].
2021-01-15 15:59:17 UTC+0100    securityGroup   UPDATE_IN_PROGRESS  -
2021-01-15 15:59:32 UTC+0100    securityGroup   UPDATE_COMPLETE -
2021-01-15 15:59:33 UTC+0100    launchConfiguration UPDATE_COMPLETE -
2021-01-15 15:59:34 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  -
2021-01-15 15:59:37 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Rolling update initiated. Terminating 2 obsolete instance(s) in batches of 1, while keeping at least 1 instance(s) in service. Waiting on resource signals with a timeout of PT5M when new instances are added to the autoscaling group.
2021-01-15 15:59:37 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Temporarily setting autoscaling group MinSize and DesiredCapacity to 3.
2021-01-15 15:59:38 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Terminating instance(s) [i-X]; replacing with 1 new instance(s).
2021-01-15 16:01:25 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  New instance(s) added to autoscaling group - Waiting on 1 resource signal(s) with a timeout of PT5M.
2021-01-15 16:01:25 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Successfully terminated instance(s) [i-X] (Progress 50%).
2021-01-15 16:01:46 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Received SUCCESS signal with UniqueId i-X
2021-01-15 16:01:47 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Terminating instance(s) [i-X]; replacing with 1 new instance(s).
2021-01-15 16:03:34 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  New instance(s) added to autoscaling group - Waiting on 1 resource signal(s) with a timeout of PT5M.
2021-01-15 16:03:34 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Received SUCCESS signal with UniqueId i-X
2021-01-15 16:03:34 UTC+0100    autoScalingGroup    UPDATE_IN_PROGRESS  Successfully terminated instance(s) [i-X] (Progress 100%).
2021-01-15 16:03:37 UTC+0100    autoScalingGroup    UPDATE_COMPLETE -
2021-01-15 16:03:37 UTC+0100    dev-cluster UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS    -
2021-01-15 16:03:38 UTC+0100    launchConfiguration DELETE_IN_PROGRESS  -
2021-01-15 16:03:39 UTC+0100    dev-cluster UPDATE_ROLLBACK_COMPLETE    -
2021-01-15 16:03:39 UTC+0100    launchConfiguration DELETE_COMPLETE -

预先感谢您的帮助!

Answer 1

对于您的直接问题，没有任何功能可以强制 ASG 在所需数量下降时一次仅删除 x 个实例

如果您还没有，您应该在 ASG 上有一个生命周期 Hook ，以触发一个脚本，告诉 ECS 将容器从实例中耗尽(我假设您使用 ECS 的上下文)。但在这种情况下，您仍然需要一次手动降低所需的 1。 https://aws.amazon.com/blogs/compute/how-to-automate-container-instance-draining-in-amazon-ecs/

如果您降低了 CloudFormation 中的期望值，那么您可以将 UpdatePolicy 附加到该组，告诉 CFN 执行 RollingUpdate 以批量替换实例，每次 1 个 https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatepolicy.html

如果您使用 ECS，设置 2 个目标跟踪扩展策略通常是一个好主意。 1 表示 CPU 预留，1 表示内存预留。如果您想强制 ASG 一次缩减超过 1 个实例，您还可以根据这些指标手动创建步进扩展策略，但在 CFN 中创建 4 个 Cloudwatch 警报将是一件痛苦的事情

另一种选择是在 ECS 中使用 CapacityProvider，这将为任何正在运行任务的实例启用实例保护