Overview
In serverless computing (FaaS), providers spin down resources when they are not in use to save costs. A 'cold start' happens when the provider must provision a new container, initialize the runtime, and load the function code before it can execute.
Factors Affecting Cold Start
- Runtime: Languages like Java or .NET typically have longer cold starts than Node.js or Python.
- Package Size: Larger code bundles take longer to load.
- VPC Configuration: Connecting a function to a VPC can add significant delay.
- Memory Allocation: Higher memory settings can sometimes reduce cold start times.
Mitigation
- Provisioned Concurrency: Keeping a certain number of instances 'warm' (at an extra cost).
- Warm-up Plugins: Periodically invoking the function to prevent it from being spun down.