Amazon Web Services SOA-C02 Exam With Confidence Using Practice Dumps

The MixedInstancesPolicy feature in Auto Scaling groups allows for the configuration of both On-Demand and Spot Instances within a single Auto Scaling group, balancing cost savings and high availability:

MixedInstancesPolicy: Enables configuration to maintain a minimum of three On-Demand Instances and add Spot Instances when prices drop, without the need to create separate launch templates.

Setting Maximum Spot Price: Ensures that additional Spot Instances are launched only when within the defined budget.

This solution offers the least management overhead, as it combines both On-Demand and Spot instances seamlessly in one configuration.

NAT Gateway resides in public subnet, and traffic should be routed from private subnet to NAT Gateway:

# Enable instance scale-in protection for specific instance.

aws autoscaling set-instance-protection --instance-ids i-5f2e8a0d --auto-scaling-group-name my-asg --protected-from-scale-in

# Disable instance scale-in protection for the specified instance.

aws autoscaling set-instance-protection --instance-ids i-5f2e8a0d --auto-scaling-group-name my-asg --no-protected-from-scale-in

To ensure that EC2 instances in an Auto Scaling group are not interrupted during message processing, the most effective method is to implement scale-in protection for the instances while they are actively processing messages. This can be done programmatically by modifying the Auto Scaling group's settings using the Amazon EC2 Auto Scaling API.

Starting Message Processing: When an instance begins processing a message, your application should make an API call to enable scale-in protection. This is done using the SetInstanceProtection action, setting the ProtectedFromScaleIn parameter to true for that specific instance.

Completing Message Processing: Once the message has been processed, another API call should be made to disable scale-in protection. This is done by calling the SetInstanceProtection action again, but this time setting the ProtectedFromScaleIn parameter to false.

This method ensures that while messages are being processed, the instances are not terminated by the Auto Scaling group regardless of any scale-in activities that might be triggered by other parameters like CPU utilization or a decrease in the number of messages in the queue.

AWS Documentation Reference:

You can refer to the AWS documentation on managing instance scale-in protection in Auto Scaling groups for more details: Instance Scale-In Protection.