Packer and post installation scripts

Packer
1

Hi everyone,
I am trying to use packer for creating managed images on azure. I want a script to be executed after the VM is launched. Just as in case of AWS instances, a linux instance has /var/lib/cloud/scripts/per-instance to run scripts once the instance is launched and per-boot for executing scripts whenever the instance is booted. Similarly, what can be done in case of Ubuntu VM on azure?

2

If the command should be executed at every reboot, you could add an entry to /etc/crontab with @reboot as time to execute.

@reboot /usr/bin/your-command

Or you could use systemd with an onshot like:

# /etc/systemd/system/rc-local.service
[Unit]
After = network-online.target
Wants = network-online.target

[Service]
Type = oneshot
RemainAfterExit = yes
ExecStart = <your-command>
ExecStart = <your-second-command>
# ...

[Install]
WantedBy = multi-user.target
3

Would specifying the path of a script instead of a command work?
For ex: @reboot /tmp/setup.sh

Similarly can we do the same with systemd? Or is it even possible to write all the commands for ExecStart?

4

Can we do something like in AWS linux AMI such as adding the file to per-instance and its executed after the instance is launched. The logs are seen in cloud-init-output.log

5

Should both be possible.

6

Hi @Wolfsrudel
Could you possibly provide an insight on this approach for a VM (ubuntu)?