Currently there is no way to fully automate the deployment of site24x7 onpremise poller in a HA configuration. Deployment can mostly be automated, however setup of HA can only be done via clickops in the browser.
Thanks for raising this. What kind of deployment tool do you use in your org? Do you use just scripts or Terraform like IaC or any other?
Currently we use IaC tools to provision & manage images with deployments utilizing bootstrap scripts.
We'll check on the possibility for deployment strategies for poller HA.
If you have any suggestions that will work for you do let know.
An API to manage the HA configuration (like is currently done in the UI) would be ideal.
We are working on the API to manage the HA configuration. I will update this thread once it is completed.