Amazon GameLift FleetIQ logic
The following diagram illustrates the role of Amazon GameLift FleetIQ when it is working with Amazon EC2 for game hosting. Its primary goal is to locate the best possible game server to host a game session and give players an optimal gameplay experience. Amazon GameLift FleetIQ defines the best resources as those that deliver the highest game hosting viability for the lowest cost. Amazon GameLift FleetIQ approaches this goal in two key ways: first by allowing only viable instance types in the Auto Scaling group, and second by placing new game sessions effectively across the group's available resources.
Fill Auto Scaling group with optimal instance types
The job of the Auto Scaling group is to launch new instances and retire old instances, maintaining a collection of hosting resources and scaling it to meet your player demand. To do this, the Auto Scaling group relies on a list of your desired instance types. The job of Amazon GameLift FleetIQ is to continually check the viability of these desired instance types and update the list for the Auto Scaling group. This process is called instance balancing. It ensures that instances in the Auto Scaling group are continually refreshed so that only currently viable instance types are used at all times.
Amazon GameLift FleetIQ affects how the Auto Scaling group selects optimal instance types in the following ways:
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It determines usage of Spot and/or On-Demand Instances. An Amazon GameLift FleetIQ game server group is configured with a balancing strategy, which influences how the Auto Scaling group uses Spot and/or On-Demand Instances. Spot Instances have lower costs due to fluctuating availability and potential interruptions, limitations that Amazon GameLift FleetIQ minimizes for game server hosting. On-Demand instances are more expensive but offer more reliable availability when you need it.
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It limits new instances to launch on viable instance types only. A Amazon GameLift FleetIQ game server group maintains a master list of your desired instance types, The instance balancing process continually evaluates each desired instance type on the list for game hosting viability, using a prediction algorithm that looks at the instance type's recent availability and interruption rate. As a result of this evaluation, Amazon GameLift FleetIQ continually updates the Auto Scaling group's list of desired instance types to include only currently viable instances types.
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It flags existing instances that are non-viable instance types. Amazon GameLift FleetIQ identifies existing instances in an Auto Scaling group that are currently non-viable instance types. These instances are flagged as draining, which means they are terminated and replaced with new instances. For instances that have game server protection turned on, termination is postponed until any active game sessions end normally.
As the Auto Scaling group launches and retires instances, it maintains a collection that is optimized for game hosting even as the availability of low-cost Spot Instance types fluctuates. Balancing activity takes place on game server groups with active instances only. Learn more about how this process works in Spot balancing process.
Place game sessions effectively
Amazon GameLift FleetIQ tracks all active game servers in the game server group and uses this information to determine the best placement for new game sessions and players.
To enable Amazon GameLift FleetIQ to track game servers, your game server software must report its status. Your custom AMI controls how new game servers processes are started and stopped on each instance. When a new game server is started, it registers with Amazon GameLift FleetIQ, indicating that it is ready to host a game session. After registering, the game server periodically reports its health and whether it is currently hosting a game session. When the game server shuts down, it de-registers with Amazon GameLift FleetIQ.
To start a new game session, your game client (or matchmaker or other client service) sends a request for a game server to Amazon GameLift FleetIQ. Amazon GameLift FleetIQ locates an available game server, claims it for the new game session, and responds with the game server ID and connection info. Your game then prompts the game server to update its status and start a new game session for incoming players.
When selecting a game server to host a new game session, Amazon GameLift FleetIQ uses the following decision-making process to optimize placement with viable low-cost Spot Instances:
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Where possible, Amazon GameLift FleetIQ places new game sessions on instances that are already hosting other game sessions. By packing (but not overloading) some instances and keeping others idle, the Auto Scaling group is able to quickly scale down idle instances when they're not needed, which lowers hosting costs.
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Amazon GameLift FleetIQ ignores instances that are flagged as draining, that is, not viable for game hosting. These instances are kept running only to support existing game sessions. They can't be used for new game sessions unless no other game servers are available.
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Amazon GameLift FleetIQ identifies all available game servers that are running on viable instances.
You can turn on game session protection for a game server group to prevent the Auto Scaling group from terminating instances with actively running game sessions.
