Increasing a fleet manually
In the previous example, we specified MinSize
and MaxSize
as 2
for the Auto Scaling Group. There is another switch that we can pass on to the New-ASAutoScalingGroup
to instruct Auto Scaling to start the fleet with the desired capacity. As we did not specify DesiredCapacity
, Auto Scaling assumes the size as the specified MinSize
. Hence, the fleet we started had the minimum two instances running. DesiredCapacity
values can be in between the MinSize
and MaxSize
of the Auto Scaling Group, and both those numbers are inclusive. Let's try to update the MaxSize
to 6
and the DesiredCapacity
of the fleet to 3
. You can do this using Update-ASAutoScalingGroup
.
PS C:\> Update-ASAutoScalingGroup -AutoScalingGroupName WebAppASG -DesiredCapacity 3 -MinSize 2 -MaxSize 6

As soon as you update the Auto Scaling Group, another EC2 instance fires up automatically. Now, you have three instances in the fleet. This way, you can manually increase the fleet size, if needed. You can also...