Interview Q&A / AWS & Cloud
AWS & Cloud interview questions
EC2, S3, Lambda, IAM and VPC basics, with when to pick which service.
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- What is the difference between a security group and a network ACL in AWS?
A security group is a stateful firewall attached to an instance's network interface, with allow rules only. A network ACL is a stateless firewall on a subnet, with numbered allow and deny rules checked in order. Because NACLs are stateless, you must allow return traffic explicitly, usually on ephemeral ports.
IntermediateIn-depth4 min read - What is an S3 presigned URL and when would you use it?
A presigned URL is a temporary link, signed with someone's credentials, that lets a person upload or download one specific S3 object without having AWS credentials. It stops working when it expires.
IntermediateQuick answer1 min read - What is the difference between AWS Secrets Manager and Systems Manager Parameter Store?
Both store configuration securely. Secrets Manager is built for secrets, with automatic rotation for supported databases and a per-secret charge. Parameter Store is simpler, has a free standard tier, and can encrypt values with KMS as SecureString.
IntermediateQuick answer1 min read