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Serverless

Lambda

Policies

Function policy Defines which AWS resources are allowed to invoke your function
Execution role
  • Defines which AWS resources your function can access
  • At minimum CloudWatch logs creategroup/createstream/putevents
  • Potentially also XRay write, SQS/Kinesis/dynamodb read to get the event data
Resource policies
  • Resources: functions, their versions and aliases, and layer versions
    • arn:aws:lambda:region:123456789012:function:my-function
    • arn:aws:lambda:region:123456789012:function:my-function:1: version
    • arn:aws:lambda:region:123456789012:function:my-function:TEST: alias
  • Use to give other services and other accounts permission to use them
  • The console updates function policies automatically when you add a trigger to give the triggering service access
Identity policies
  • To give users the ability to create functions with limited permissions, constrain what roles they can iam:PassRole on
  • To give users the ability to add resource permissions to functions so they can be invoked, but only from specific sources

Other

Integrity
VPC access
  • Can access resources in a VPC if subnet and security group is specified
  • No internet access unless there is a NAT in the VPC
  • No AWS service access unless there is internet access or VPC gateways
  • Role needs ability to create network interfaces in each subnet (and VPC must have ENI capacity & subnets must have spare IPs)
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