We are trying to run few bash commands in cloud formation template in AWS.
We followed the following blog of AWS to run CommandRunner utilty in cloud formation template. https://aws.amazon.com/blogs/mt/running-bash-commands-in-aws-cloudformation-templates/
Resources:
CommandRunner:
Type: AWSUtility::CloudFormation::CommandRunner
Properties:
Command: 'echo HelloWorld > /command-output.txt'
Outputs:
Op1:
Description: Test output
Value:
Fn::GetAtt: CommandRunner.Output
Facing following error while running command utility in cloud formation template.
Resource handler returned message: "Index: 0, Size: 0" (RequestToken: c99903a7-****-0c58-010c-4fa03699fcfd, HandlerErrorCode: InternalFailure)
Stack ID(s) / Stack ARN: arn:aws:cloudformation:eu-west-2:*****:stack/comandrunner-test-iops/ **
The error message is not descriptive enough to identify the root cause.
When contacted AWS Supported team, they gave the following response.
The Index: 0, Size: 0 error usually happens because you may not have a default VPC in the eu-west-2 region (P.S.: I am not able to verify this since I do not have access to your account).
In general, CommandRunner uses the default VPC to run the command, but when it doesn’t exist this error is thrown. You can still run the CommandRunner without a default VPC, by specifying the SubnetId property.
I also found an active issue pulled in on the github repository to improve the error handling for this error when it occurs on CloudFormation.
After their response, we added Subnet id and security group id to the template.
Give private subnet id.
Parameters:
ReqSubnetId:
Type: String
Description: Please enter Subnet id so that command runner can execute
Default: subnet-0sampleid28474
ReqSecurityGroupId:
Type: String
Description: Please enter security group id so that command runner can execute
Default: sg-03samplesecuritygroupid
Resources:
CommandRunner:
Type: AWSUtility::CloudFormation::CommandRunner
Properties:
Command: 'echo HelloWorld > /command-output.txt'
SubnetId: !Ref ReqSubnetId
SecurityGroupId: !Ref ReqSecurityGroupId
Outputs:
Op1:
Description: Test output
Value:
Fn::GetAtt: CommandRunner.Output
Options supported for Type: AWSUtility::CloudFormation::CommandRunner are
Type: AWSUtility::CloudFormation::CommandRunner
Properties:
Command: String
Role: String
LogGroup: String
SubnetId: String
KeyId: String
SecurityGroupId: String