run a single script after droplet deployment

Hey 👋

Yep, you can do this with Cloud init:

https://docs.digitalocean.com/products/droplets/how-to/automate-setup-with-cloud-init/

The above documentation goes over on how to set this all up, but let me know if you have any questions!

Here’s a general approach you could take:

1. Add your script is present in the snapshot, for example /root/post-deploy-script.sh.
2. Set up a cloud-config file or user data script that will run when the Droplet first boots. This can be done through the DigitalOcean control panel when creating the Droplet, or via their API.
3. In the cloud-config or user data, include a command to execute your script.

For example, your user data might look something like this:

#cloud-config
runcmd:
  - /bin/bash /root/post-deploy-script.sh

Alternatively, instead of creating the script file separately, you could define it directly in your Cloud init file as per the documentation above, e.g.:

#cloud-config
users:
  - name: example-user
    shell: /bin/bash
    sudo: ['ALL=(ALL) NOPASSWD:ALL']
    ssh_import_id:
      - gh:<your-GitHub-username>
disable_root: true
packages:
  - nginx
runcmd:
  - 'export PUBLIC_IPV4=$(curl -s http://169.254.169.254/metadata/v1/interfaces/public/0/ipv4/address)'
  - 'echo Droplet: $(hostname), IP Address: $PUBLIC_IPV4 > /var/www/html/index.html'

- Bobby

Heya,

Yep, that is what Cloud-init is for and can help you greatly. Here is an example usage of Cloud-init:

https://www.digitalocean.com/community/questions/automate-nginx-reverse-proxy-setup-for-node-js-with-cloud-init

You can take inspiration from there.

There are a few ways to do it. You can use rc.local file or Cloud init to do it. You can also use crontab for this like below,

Create the script,

nano /opt/post-startup.sh

Paste your commands,

#!/bin/bash

#Add your commands below

Make it executable

chmod +x /opt/post-startup.sh

And then add following to your crontab,

@reboot bash /opt/post-startup.sh > /dev/null 2>&1

Source Linux: How to execute a bash script at system startup using crontab