Ravi Sir's Cards › AWS
Failure isolation
What is a VPC: your own private network inside one AWS Region, example ThreeTierVpc 10.0.0.0/16.
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What this card says
Why do we need it?
If email code throws, inventory must still update. Shared one-Lambda fan-out does not isolate well.
What is it?
Separate queues and Lambdas isolate failures. Each queue can have its own DLQ and retry count.
How to do it
Set maxReceiveCount 3 → DLQ on each queue. Idempotent PutItem keyed by orderId+worker type.
DLQ
Example
Poison email message lands in email-DLQ; inventory table still shows reserved for that orderId.