Specific Auto-Scaling group Cloudformation AWS

Question

I have an auto scaling group in AWS so i can change stack size of instances created by CF. However when i want to reduce the stack it will terminate random instances in the stack.

I need to know if its possible to reduce stack size in CF but leave specific instances in the stack running using the scaling group?

      "WebServerScaleUpPolicy" : {
  "Type" : "AWS::AutoScaling::ScalingPolicy",
  "Properties" : {
    "AdjustmentType" : "ChangeInCapacity",
    "AutoScalingGroupName" : { "Ref" : "AutoScalingServerGroup" },
    "Cooldown" : "60",
    "ScalingAdjustment" : "1"
  }
},
"WebServerScaleDownPolicy" : {
  "Type" : "AWS::AutoScaling::ScalingPolicy",
  "Properties" : {
    "AdjustmentType" : "ChangeInCapacity",
    "AutoScalingGroupName" : { "Ref" : "AutoScalingServerGroup" },
    "Cooldown" : "60",
    "ScalingAdjustment" : "-1"
  }
}

Any Help Appreciated.

mcfinnigan mcfinnigan · Accepted Answer · 2018-02-16T12:45:57

Look into instance scale-in protection, as detailed in this AWS blog post.

I don't use CloudFormation so I'm not sure of the level of support it has for Autoscaling customisation, but this post has a workaround that may work for you.

Specific Auto-Scaling group Cloudformation AWS

2 Answers