I have successfully provisioned managed instance groups using terraform. Now I am turning my attention to health checks. I would like to confirm that the VM instances that are part of my MIG will need public IPs in order to accept health checks.
I gather that even under these conditions, I may use firewall rules to only allow traffic from the Google probers as described here: Health checks overview | Load Balancing | Google Cloud
The application running on these instances otherwise does not need to accept any HTTP requests.
I’m a bit confused because there seems to be some debate as to whether an external IP is required: load balancing - Do I need external IPs for Managed Instance Group instances serving as a GLB back-end? - Server Fault