Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, 
      see Getting Started with Amazon Web Services in China
         (PDF). 
    Target-based auto scaling
Target-based auto scaling for Amazon GameLift Servers adjusts capacity levels based on the fleet metric
            PercentAvailableGameSessions. This metric represents the fleet's available
        buffer for sudden increases in player demand.
The primary reason for maintaining a capacity buffer is player wait time. When game
        session slots are ready and waiting, it takes seconds to get new players into game sessions.
        If no resources are available, players must wait for existing game sessions to end or for
        new resources to become available. It can take minutes to start up new instances and server
        processes.
When setting up target-based auto scaling, specify the size of the buffer that you want
        the fleet to maintain. Because PercentAvailableGameSessions measures the
        percentage of available resources, the actual buffer size is a percentage of the total fleet
        capacity. Amazon GameLift Servers adds or removes instances to maintain the target buffer size. With a large
        buffer, you minimize wait time, but you also pay for extra resources that you may not use.
        If your players are more tolerant of wait times, you can lower costs by setting a small
        buffer.
        To set target-based auto
                scaling
        
            - Console
 - 
                    
Open the 
         Amazon GameLift Servers console.
- 
            
In the navigation pane, choose Hosting, Fleets.
         - 
            
On the Fleets page, choose the name of an active fleet to open the fleet's 
                detail page.
         - 
                            
Choose the Scaling tab. This tab displays the
                                fleet's historical scaling metrics and contains controls for
                                adjusting current scaling settings. 
                         - 
                            
Under Scaling capacity, check that the
                                    Min size and Max size
                                limits are appropriate for the fleet. With auto scaling enabled,
                                capacity adjusts between these two limits.
                         - 
                            
In Target-based auto-scaling policy, choose
                                    Edit.
                         - 
                            
In the Edit target-based auto-scaling policy
                                dialog box, for Percent available game
                                sessions, set the percentage that you want to maintain,
                                and then choose Confirm. After you've confirmed
                                the settings, Amazon GameLift Servers adds a new target-based policy under
                                    Target-based auto-scaling policy.
                         
 
                 
            - Amazon CLI
 - 
                    
- 
                            
Set capacity limits. Set the
                                limit values using the update-fleet-capacity command. For more information,
                                see Set Amazon GameLift Servers capacity limits.
                         - 
                            
Create a new policy. Open a
                                command-line window and use the put-scaling-policy command with your policy's parameter
                                settings. To update an existing policy, specify the policy's name
                                and provide a complete version of the updated policy.
                            --fleet-id <unique fleet identifier>
--name "<unique policy name>"
--policy-type <target- or rule-based policy>
--metric-name <name of metric>
--target-configuration <buffer size>
                            Example:
                            aws gamelift put-scaling-policy \
    --fleet-id "fleet-2222bbbb-33cc-44dd-55ee-6666ffff77aa" \
    --name "My_Target_Policy_1" \
    --policy-type "TargetBased" \
    --metric-name "PercentAvailableGameSessions" \
    --target-configuration "TargetValue=5"