Auto Scaling Groups
- It contains a collection of Amazon EC2 instances
- All instances are treated as single logical group
- Grouping helps in automatic scaling and management.
- Following EC2 Auto Scaling features are applied on all instances in group
- health check replacements
- scaling policies.
- Group size depends on count of instances as per desired capacity.
- Can adjust group size to meet demand, either manually or by using automatic scaling.
- Group starts by launching enough instances as per capacity.
- Group maintains capacity by conducting health checks periodically on instances
- Group maintains fixed number of instances even if instance becomes unhealthy.
- Unhealthy instance is terminated by group and another one is launched
- Scaling policies dynamically increase or decrease instances in group to address need
- Scaling policy adjusts capacity between minimum and maximum capacity values
- Group can also launch On-Demand Instances, Spot Instances, or both.
- Availability of spot instances varies
- If multiple Availability Zones are specified during instance launch, capacity is distributed across these Availability Zones.
