feat: Write detailed output from bootstrap.sh to log file

[jebbens]

What would you like to be added:
Write detailed output from bootstrap.sh to a log file, e.g.

exec > >(tee /var/log/bootstrap.log|logger -t user-data -s 2>/dev/console) 2>&1
set -x

Needs to be done in a way that does not overwrite user-provided user-data from custom launch template.

Why is this needed:
When dealing with custom launch templates, e.g. to configure for use with a proxy, it is useful to have the complete output of all user data in a log file for troubleshooting.

[cartermckinnon]

The bootstrap logs should already be present in /var/log/cloud-init-output.log, but adding more details (in a more uniform format) sounds like a great idea to me. Is there any information in particular you're looking for?

[jebbens]

I don't see very much in cloud-init-output.log. I think if we added the two lines of code I referenced above (per recommendation from here, we'd get more useful output. Also, if a user provides their own user-data in a different MIME message part that runs before the bootstrap.sh, and outputs it to that same file, it may get overwritten by the user-data behind it (if it writes to the same file). So, we could output logs from bootstrap.sh to a separate file, e.g. /var/log/bootstrap.log to avoid that conflict.

[cartermckinnon]

Any stdout from user data will appear in cloud-init-output.log. We recently added more logging to the bootstrap script, so I'm going to close this issue. Let me know if #1276 doesn't meet your needs.

[jebbens]

Looking at nodes I just launched, my cloud-init-output.log looks nothing like my user-data.log. All i see in the former is a short log of network interfaces and routing information. Not sure why I'm not seeing all of the output from the user-data that I see in the latter. Note these are self-managed nodes.