Build a queue for Spot Instances - Amazon GameLift Servers
Implementation tasksBest practices
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Build a queue for Spot Instances

You can achieve of potentially significant savings in hosting costs by using Spot fleets. For more details about Spot fleets and how to use them, see On-Demand Instances versus Spot Instances.

If your game hosting solution includes Spot fleets, you must use a game session placement queue. Amazon GameLift Servers uses queues to search across multiple game hosting resources and select the best one available to host a new game session. With Spot fleets, queues are particularly important for minimizing hosting costs and avoiding possible Spot interruptions. This topic helps you set up a resilient queue that can continue to host games for players even in the event of interruptions, slowdowns and outages. You can customize how the queue prioritizes available hosting resources based on several factors including hosting cost.

Are you using FlexMatch for matchmaking? You can use a queue with Spot fleets to make game session placements for your matches.

Implementation tasks for Spot fleets

When creating or updating your game hosting solution to use Spot fleets, complete the following tasks. For more detailed guidance on how to build a queue that optimizes Spot availability and resiliency, see Reduce game hosting costs with Spot fleets .

  1. Choose and create a set of fleet destinations for your game session queue.

    Start by deciding where you want your queue to place game sessions. A queue can search across multiple fleets to find the best possible placement. Each fleet has one instance type but can have multiple geographic locations. Queues with fleets that offer variety in both location and instance type are more likely to make successful placements. See these best practices for designing an effective and resilient Spot-optimized queue.

  2. Create your Spot-optimized game session queue.

    Create a queue and configure it for your Spot fleets. See Create a game session queue for help creating and configuring the new queue. You can use the Amazon GameLift Servers console or the Amazon CLI to create or edit a queue.

    • Add the fleet destinations from Step 1.

    • Prioritize the destination order as appropriate. By default, Amazon GameLift Servers prioritizes by cost before destination, so destination order is used only when the lowest costs between destinations are equal.

    • If you want to prioritize game hosting cost before player latency, provide a custom placement priority. See Prioritize game session placement.

  3. Update other components in your solution to use the new queue.

    When your solution uses a Spot-optimized queue to start new game sessions, the queue automatically avoids placing game sessions with fleets that have a high likelihood of interruption. It instead searches all viable fleets for resources that match your defined priorities, including player latency, hosting cost, and destination order.

    • If you're not using FlexMatch – Update your backend service to specify the new Spot-optimized queue in game session requests. The backend service makes API requests to Amazon GameLift Servers on behalf of your game client (using StartGameSessionPlacement()), and each request must specify a queue name. For help implementing game session placements in your game client, see Create game sessions.

    • If you are using FlexMatch – Update your matchmaking configuration to send game session requests to the new Spot-optimized queue. When the matchmaking system forms a player match, it sends a game session placement request to the designated queue to start a new game session for the match. Only matchmaking configurations with FlexMatch mode set to "Managed" can designate a placement queue. You can update a matchmaking configuration using the Amazon CLI or the Amazon GameLift Servers console (see Edit a matchmaking configuration).

  4. Review the performance of your Spot fleets and queues.

    View Amazon GameLift Servers metrics in the Amazon GameLift Servers console or with Amazon CloudWatch to review performance. For more information about Amazon GameLift Servers metrics, see Monitor Amazon GameLift Servers with Amazon CloudWatch. Key metrics include:

    • Interruption rate – Use the InstanceInterruptions and GameSessionInterruptions metrics to track the number and frequency of Spot-related interruptions for instances and game sessions. Game sessions on reclaimed instances have a status of TERMINATED and a status reason of INTERRUPTED.

    • Queue effectiveness – Track placement success rates, average wait time, and queue depth to confirm that Spot fleets don't impact your queue performance.

    • Fleet usage – Monitor data on instances, game sessions and player sessions. Usage for your On-Demand fleets can be an indicator that queues are avoiding placements into your Spot fleets to avoid disruption.

Best practices for queues with Spot fleets

Use the following best practices when creating fleets and queues for Spot instances.

  • Expand your queue's geographic coverage. Even if your players are clustered in a single Amazon Web Services Region, add adjacent locations to your Spot fleet. This approach improves the queue's ability to maintain capacity during regional slowdowns, outages, and Spot interruptions. Multi-location fleets work with both Spot and On-Demand instances.

  • Diversify your queue's instance type coverage. Amazon GameLift Servers evaluates Spot viability based on instance type, so having Spot fleets with a variety of instance types reduces the chance that multiple Spot fleets are nonviable at the same time. Include at least two Spot fleets with different instances types each location.

    Note

    Pricing is based on the instances you use, not the number of fleets. Running five fleets with 10 instances each is the same as running one fleet with 50 instances of similar cost. Pricing varies by instance type, size, and location.

    Tips for grouping Spot instance types:

    • Use instance types in the same family, such as m6g.medium, m6g.large, and m6g.xlarge. Larger instance types cost more, but can also host more game sessions at a time.

    • Select widely available instances types. Typically, older generation families (such as C5, M5, and R5) and common sizes (such as .large, .xlarge, and .2xlarge) have better availability.

    • Check the 30-90 day pricing history in the Amazon GameLift Servers console. Look for instance types with consistent availability patterns.

    • Use the Amazon GameLift Servers console, fleet creation tool, to explore location coverage for instance types.

  • Add On-Demand fleets for backup capacity. Game hosting can switch to On-Demand fleets whenever Spot fleets are unavailable. Put at least one On-Demand fleet in each location to maintain low player latency. Add auto-scaling to your backup On-Demand fleets, so you can keep them scaled down until they're needed.

  • Assign aliases to all fleet destinations. Create aliases for each of your queue's destinations. Aliases make it easier and more efficient whenever you need to replace fleets.

  • Apply a queue prioritization strategy. You can customize how a queue prioritizes where to place game sessions (see Prioritize game session placement for more details). For Spot-optimized queues, prioritizing by cost ensures that low-cost Spot fleets are used whenever possible.

    You can also prioritize certain fleets by specifying a destination order. For example, some users designate a set of primary fleets for regular use and also a set of secondary fleets as backup. In this scenario, set the queue's destination order to list the primary fleets first. Then configure the queue's priority order with destination followed by cost.