The role defined for the function cannot be assumed by Lambda

Question

I\'m getting the error \"The role defined for the function cannot be assumed by Lambda\" when I\'m trying to create a lambda function with create-function command.

Answer 1

I am just learning to use the AWS CLI and ran into this issue.

I am using a series of PowerShell scripts to deploy an entire AWS architecture. My createRole.ps1 script contains:

aws iam create-role `
--role-name $roleName `
--assume-role-policy-document file://myRoleTrustPolicy.json

The file myRoleTrustPolicy.json contains:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": [
          "elasticmapreduce.amazonaws.com",
          "datapipeline.amazonaws.com",
          "lambda.amazonaws.com"
        ]
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

It is the "lambda.amazonaws.com" line that was missing from Service list that was causing the issue.

Once I fixed that, the invocation of aws lambda create-function worked great.

aws lambda create-function `
--function-name $fn `
--runtime java8 `
--role $currentRoleARN `
--handler "handleRequest" `
--memory-size 128 `
--zip-file $jarFile