I have a shell script(userdata file) and wondering is there a CLI command parameter that allows user to launch Cloudformation stack with userdata file?
7
votes
what is the difference between your so called "userdata file" and the template itself?
– Vladimir Mukhin
Can you explain your use case some more?
– stevepkr84
Userdata scripts for say cloudinit can be fairly long shell scripts. Editing them inline in the template can be a royal pain. It is nice to have them in their own file and inject it into the template when creating it.
– John Eikenberry
2 Answers
19
votes
Inside your template, use a CloudFormation parameter for the instance userdata:
{
"Parameters": {
"UserData": {
"Type": "String"
}
},
"Resources": {
"Instance": {
"Type" : "AWS::EC2::Instance",
"Properties" : {
"UserData" : { "Ref" : "UserData" },
...
}
},
...
}
}
Assuming you're using a Unix-like command line environment, create your stack like this:
aws cloudformation create-stack --stack-name myStack \
--template-body file://myStack.json \
--parameters ParameterKey=UserData,ParameterValue=$(base64 -w0 userdata.sh)
1
votes
Your user-data must exist in the CloudFormation template when you create the stack. You can write a script to read in your user-data from the file and insert it into the CloudFormation stack prior to creating the stack. Note that you may need to make formatting changes to the userdata (see http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html#cfn-ec2-instance-userdata).
