I'm writing a CloudFormation template and I'm trying to debug the user-data script I provide in the template. How can I run the cloud-init manually and make it perform the same actions it does when starting a new instance?
Update:
There is upstream documentation for this now.
You can just run it like this:
/usr/bin/cloud-init -d init
This runs the cloud init setup with the initial modules. (The -d option is for debug) If want to run all the modules you have to run:
/usr/bin/cloud-init -d modules
Keep in mind that the second time you run these it doesn't do much since it has already run at boot time. To force to run after boot time you can run from the command line:
( cd /var/lib/cloud/ && sudo rm -rf * )
In older versions the equivalent of cloud-init init is:
/usr/bin/cloud-init start
You may also find this question useful although it applies to the older versions of cloud-init: How do I make cloud-init startup scripts run every time my EC2 instance boots?
The documentation for cloud init here just gives you examples. But it doesn't explain the command line options or each one of the modules, so you have to play around with different values in the config to get your desired results. Of course you can also look at the code.