Lightsail launch script breaks instance

Question

As per title, every lightsail instance created with a launch script are broken.

SSH will not set up correctly, even with my key I'll get denied, so I can't see where did it go wrong.

Is there a specific way to exit the script? Should I not include a shebang? If so, which shell is used during lightsail setup?

Here's what my script looks like:

```
#!/bin/bash

exec &>> '/tmp/launch.log'

tmp_dir="$(mktemp -d)"
cd "$tmp_dir" || exit 1

## dnf install epel-release
## Install a bunch of other packages
## Also grabs configuation files
## Plus SELinux contexts

logger -t launch_log < '/tmp/launch.log'
exit
```

Answer

Hi,

Your instance should be accessible using Lightsail Connect or terminal-based SSH and the SSH key selected during instance creation. If you can connect to your instance, you can view the execution output of the provided userdata script at `/var/log/cloud-init-output.log` to help with debugging.

If you cannot connect to your instance, I recommend [creating a root volume snapshot](https://docs.aws.amazon.com/lightsail/latest/userguide/amazon-lightsail-create-an-instance-root-volume-snapshot.html) and attaching it to a known working instance you can connect to and inspect the cloud-init output.

Answer

Hello.

I recommend that you create a snapshot of the root volume using the steps in the document below, mount it on a healthy Lightsail, and then check the system logs, etc.  
https://docs.aws.amazon.com/lightsail/latest/userguide/amazon-lightsail-create-an-instance-root-volume-snapshot.html

Looking at the shell script, most of it is commented out, so it appears that no commands that affect SSH are executed.  
Can I access it via a browser using the steps in the document below?  
https://docs.aws.amazon.com/lightsail/latest/userguide/lightsail-how-to-connect-to-your-instance-virtual-private-server.html

Lightsail launch script breaks instance

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