EC2 Amazon - User Data Not Working For Bundled/Snapshot AMI

Question

I started an default instance of EC2 Wowza AMI (LINUX) and then I bundled/snapshot it via 'ec2-bundle-vol', uploaded it to s3 and registered the AMI.

When I start the bundled AMI with user data (zip file) with a script, it doesn't seem to execute it.

But when I start a default instance with the same user data (zip file), it works.

Does anyone know why my bundled AMI is not executing the user data I specify?

Thanks.

Answer 1

I had the same issue. Looking at our script I discovered that we were removing a cloud init dependancy in the script, making it a run once operation. The dependancy in question was boto.

Answer 2

The user data mechanism on EC2 allows a script on the image to download the startup package as a file via HTTP from a link-local address (169.254.something) - if it's plaintext, it will execute directly. If it's compressed data, wowza startup will unpack it to /opt/working - the Wowza startup process is logged to wowzamediaserver_startup.log in Wowza's logs directory.

Answer 3

I'm not familiar with wowza or how they have their AMIs setup but...

On its own the ec2 user data does nothing - it only has relevance because a script running on that machine checks for the presence of the user data and does something with it.

Sometimes these scripts are set so that they only do stuff on the instance's first boot, they then drop a file somewhere so that on subsequent reboots the startup scripts aren't rerun.

If the wowza amis work on this basis then when you first boot up the ami this process is followed, so the data you've saved into the new AMI includes the "don't run startup scripts again" file. If this is the case you'd need to delete that file before creating your ami.