AWS - Auto Scaling

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083.mp4 084.mp4 – Auto Scaling

  • can scale up / down

  • only scale horizontal

  • can scale accross AZ (can’t scale accross region !)

  • params: min size; max size; desired capacity (init size)

  • “Launch configuration”

    • AMI type; Instance Type; Key pair; Security Groups
    • Optional: spot instance bid pricing

  • Autoscaling group

    • unhealth instance will be terminted and replaced

  • Scaling plans (?)

  • Scaling Policy

    • how to trigger: Alarm + policy to decide how to scale
    • trigger what action: ChangeInCapacity; ExactCapacity; PercentChangeInCapacity

  • Scaling Policy Types:

    • Simple Scaling
    • Step Scaling (new feature): allow small changes,like 20% more capacity when 40%<CPU<70%

AutoScaling Margin

Scaling options
https://docs.aws.amazon.com/autoscaling/ec2/userguide/scaling_plan.html

Save cost
https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-instance-termination.html

PercentChangeInCapacity
https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_PutScalingPolicy.html

The order of execution for scheduled actions ; time confliction
https://docs.aws.amazon.com/autoscaling/ec2/userguide/schedule_time.html

AutoScaling Lifecycle Hooks; Action Result: ABANDON / CONTINUE
自动起来的实例，可以给一定时间装软件搞配置，一切ready返回信号（abandon或者continue），如果是continue，这个实例就可以加入集群了。
https://docs.aws.amazon.com/autoscaling/ec2/userguide/lifecycle-hooks.html

health check grace period
autoscaling检查新加入实例的健康状态之前必须等待的时间。（确保新实例完全ready再检查）
https://docs.aws.amazon.com/autoscaling/ec2/userguide/healthcheck.html

AutoScaling Standby State
把怀疑有问题的实例设置成standby state状态（还属于集群的一部分），检查其状态，修好了归队。
https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-enter-exit-standby.html

Merge single zone autoscaling group into multi zone group
可以把一模一样的分布在不同AZ的集群merge到一起
https://docs.aws.amazon.com/autoscaling/ec2/userguide/merge-auto-scaling-groups.html

describe-scaling-activities command
https://docs.aws.amazon.com/cli/latest/reference/autoscaling/describe-scaling-activities.html

Error Msg: Autoscaling: 《》instance(s) are already running.
说明hit当初设置的集群实例数上限了。
https://docs.aws.amazon.com/autoscaling/ec2/userguide/ts-as-capacity.html

Reward Makes Perfect
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