Prioritize game session placement - Amazon GameLift
Customize how a queue prioritizes game session placementsPrioritize placements by player latencyPrioritize placements by location
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Prioritize game session placement

Amazon GameLift uses an algorithm to determine how to prioritize a queue's destinations and determine where to place a new game session. The algorithm is based on an ordered set of criteria. You can use the default priority order, or you can customize the order. You can edit a queue's priority order at any time.

Default priority order

  1. Latency – If the game session placement request includes location-specific latency data for players, Amazon GameLift calculates the average player latency in each location and attempts to place a game session in a fleet location with the lowest average.

  2. Cost – If a request doesn't include latency data, or if multiple fleets have equal latency, then Amazon GameLift evaluates the hosting cost of each fleet. A fleet's hosting cost varies based on fleet type (Spot or On-Demand), instance type, and location.

  3. Destination – If multiple fleets have equal latency and costs, then Amazon GameLift prioritizes fleets based on the destination order as listed in the queue configuration.

  4. Location – For queues with multi-location fleets, if all other criteria are equal, then Amazon GameLift prioritizes the fleet's locations based on alphabetical order.

Customize how a queue prioritizes game session placements

You can choose to customize how a queue prioritizes the placement criteria. The queue applies the custom prioritization to all game session placement requests that it receives.

Note

If you create a custom priority configuration and don't include all four criteria, Amazon GameLift automatically appends any missing criteria in the default order.

To customize a queue’s priority configuration

Use the Amazon GameLift console or the Amazon Command Line Interface (Amazon CLI) to create a custom priority configuration.

Console

In the Amazon GameLift console, you can customize a queue's priorities when creating a new queue or updating an existing queue. Select an Amazon Region to work in.

Open the console’s left navigation bar and choose Queues. On the Queues page, select an existing queue and choose Edit.

  1. Go to the section Game session placement priority. Drag and drop each priority criteria to create the order you want.

  2. Go to the section Location order. Add any locations that you want to prioritize. This list is useful when the queue has fleets with multiple locations. At a minimum, you must specify one location. The locations you specify here are prioritized first, followed by all other locations in the queue's destinations.

  3. Choose Save changes.

Amazon CLI

Use the update-game-session-queue command with the --priority-configuration option to customize a queue's priority order. Amazon GameLift updates a queue in your current default Amazon Region, or you can add a --region tag to specify a different Amazon Region.

The following example request adds or updates the priority configuration for a specified queue

aws gamelift update-game-session-queue \ 
    --name "example-queue-with-priority"
    --priority-configuration PriorityOrder="COST','LOCATION","DESTINATION",LocationOrder="us-east-1","us-east-2","ca-central-1","us-west-2" \

Prioritize placements by player latency

If you want to give your players the best possible player experience and ensure minimal latency, take the following steps when setting up your game session placement system:

  • Set your queue to prioritize latency when choosing where to place game sessions. Latency is at the top of the priority list by default. You can also customize your queue's priority configuration and choose where to put latency in priority order.

  • Set up player latency policies for your queue. Latency policies let you set hard limits on the amount of latency to allow in a game session placement. If Amazon GameLift can't place a game session without exceeding the limits, the placement request will time out and fail. You can set up a single latency policy, or you can create a series of policies that gradually relax the latency limit over time. With a series of policies, you can specify very low initial latency limits, and still accommodate players with higher latencies after a short delay. For details on creating latency policies, see Create a player latency policy.

  • When making game session placement requests (see StartGameSessionPlacement), include latency data for each player. Player latency data includes a value for every possible location where a game session might be placed. For example, for a queue that places game sessions in Amazon Web Services Regions us-east-2 and ca-central-1, latency data might look like this: 

    "PlayerLatencies": [ 
    { "LatencyInMilliseconds": 100, "PlayerId": "player1", "RegionIdentifier": "us-east-2" },
    { "LatencyInMilliseconds": 100, "PlayerId": "player1", "RegionIdentifier": "ca-central-1" },
    { "LatencyInMilliseconds": 150, "PlayerId": "player2", "RegionIdentifier": "us-east-2" },
    { "LatencyInMilliseconds": 150, "PlayerId": "player2", "RegionIdentifier": "ca-central-1" }
  ]

Prioritize placements by location

You can configure a queue to make game session placements based on a prioritized list of geographic locations. Location is one of the criteria that determines how a queue chooses where to place a new game session. By default, location is prioritized fourth, after latency, cost, and destination.

For game session placement, destination and location have somewhat different meanings:

  • Destination refers to a specific fleet and includes all the fleet's hosting resources, wherever they're deployed. When prioritizing by destination, Amazon GameLift might make a placement with any location in the fleet. Multi-location managed fleets and Anywhere fleets can have hosting resources that are deployed to one or more locations.

  • Location refers to a specific geographic position where a fleet's hosting resources are deployed. A fleet can have multiple locations, which might include Amazon Web Services Regions, Local Zones, or custom locations (for an Anywhere fleet). A single-location managed fleet has one location and it is always an Amazon Web Services Region. A multi-location managed fleet has a home Region and can have remote locations. An Anywhere fleet has one or more custom locations.

When prioritizing placements by location, Amazon GameLift looks for any queue destinations that include the priority location and searches them for an available hosting resource. If there are multiple destinations with the priority location, Amazon GameLift moves on to the next priority criteria (cost, latency, destination).

There are several ways that you can influence how a queue's locations are prioritized

  • Configure how the queue handles all game session placement requests:

    • Add a priority configuration to the queue. A queue's priority configuration includes an ordered list of locations. You can specify one or more locations to prioritize. This list doesn't exclude any locations, it simply tells Amazon GameLift where to look first for an available hosting resource. A common use for an ordered location list is when you want to funnel most traffic to one or more specific geographic locations and use additional locations as backup capacity. Add a priority configuration by calling UpdateGameSessionQueue.

    • Add a filter configuration to the queue. A filter configuration is an allow list for the queue. It tells Amazon GameLift to ignore any locations that aren't on the list when looking for an available hosting resource. There are two common uses for a filter configuration. First, for fleets with multiple locations, you might use a filter to exclude some of the fleet's locations. Second, you might want to temporarily disallow placements on a certain location; for example, a location might be experiencing transitory issues. Because you can update a queue's filter configuration at any time, you can easily add and remove locations as needed. Add a filter configuration by calling UpdateGameSessionQueue.

  • Use special instructions for individual placement requests:

    • Include a priority override list in a game session placement request. You can provide an alternate priority list of locations with any StartGameSessionPlacement request. This list effectively replaces the queue's configured prioritization for locations for that one request only. It doesn't impact any other requests. This override feature has a few requirements:

      • Use an override list only with a queue that has a priority configuration in place with LOCATION as the first priority.

      • Don't include player latency data in the same placement request. Including latency data sets up conflicts when prioritizing locations that Amazon GameLift can't resolve.

      • Decide how you want Amazon GameLift to proceed if it can't find an available resource on the priority override list. Choose between falling back to the queue's other locations, or limit placements to the override list. By default, Amazon GameLift falls back to attempt placement on the queue's other locations.

      • Update the queue's filter configuration as needed, such as adding locations on the override list. The override list doesn't invalidate the filter list.