Lambda Managed Instances runtimes
Lambda processes requests differently when using Lambda Managed Instances. Instead of handling requests sequentially in each execution environment, Lambda Managed Instances process multiple requests concurrently within each execution environment. This change in execution model means that functions using Lambda Managed Instances need to consider thread safety, state management, and context isolation, concerns which do not arise in the Lambda (default) single-concurrency model. In addition, the multi-concurrency implementation varies between runtimes.
Supported runtimes
The following runtimes support Lambda Managed Instances:
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Java: Java 21 and later.
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Python: Python 3.13 and later.
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Node.js: Node.js 22 and later.
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.NET: .NET 8 and later.
Runtime-specific considerations
Each runtime implements multi-concurrency differently. You need to understand how multi-concurrency is implemented in your chosen programming language to apply the appropriate concurrency best practices.
Java
Uses a single process with OS threads for concurrency. Multiple threads execute the handler method simultaneously, requiring thread-safe handling of state and shared resources.
Python
Uses multiple Python processes where each concurrent request runs in a separate process. This protects against most concurrency issues, though care is required for shared resources such as the /tmp directory.
Node.js
Uses worker threads
.NET
Uses .NET Tasks with asynchronous processing of multiple concurrent requests. Requires safe handling of state and shared resources.
Next steps
For detailed information about each runtime, see the following topics:
