Overview
The exam likes to check whether you know the Lambda limits. These limits are per region. There are execution limits and deployment limits.
Execution Limits
| Limit | Value |
|---|---|
| Memory allocation | 128 MB to 10,240 MB (10 GB), in 1 MB increments |
| vCPU | More memory means more vCPU |
| Maximum execution time | 900 seconds (15 minutes). Anything longer is not a good Lambda use case |
| Environment variables | Up to 4 KB |
Disk capacity in /tmp |
Up to 10 GB (temp space for pulling big files while the function runs) |
| Concurrent executions | 1000 standard default (can be increased by request); new accounts may start lower |
1,000 is the standard default; new accounts may start with reduced quotas that AWS raises automatically. Separately, each function scales by 1,000 execution environments every 10 s. The exam may still use the course figure. AWS source
Memory is set in 1 MB increments from 128 MB to 10,240 MB. The course said 64 MB increments. AWS source
The default of 1000 concurrent executions can be raised with a request, but it is good to use reserved concurrency early on. See 04-Lambda-Concurrency.
Deployment Limits
| Limit | Value |
|---|---|
| Compressed deployment package (.zip) | 50 (the unit is garbled in the transcript, presumably MB) |
| Uncompressed deployment (code + dependencies) | 250 MB |
| Large files | Use the /tmp directory instead |
| Environment variables | 4 KB |
Exam Reasoning
If a question says you need 30 GB of RAM, 30 minutes of execution time, or a 3 GB big file, then Lambda is not the right way to run that workload.
Questions & Answers
Q1: A job needs 30 minutes of runtime. Use Lambda?
Answer:
No. Max execution time is 15 minutes (900 s).
Q2: A function needs 30 GB of RAM. Use Lambda?
Answer:
No. Max memory is 10 GB.
Q3: Where do you put large files a function needs?
Answer:
In the /tmp directory, up to 10 GB, not in the deployment package.
Q4: What is the default concurrency limit and can it grow?
Answer:
1000 concurrent executions. Yes, via a limit increase request.
Check yourself
Quiz
Flashcards
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