Can we use Unmanaged Instance group for external HTTPS load balancer in GCP

Question

I am planning to create an External HTTPS load balancer on GCP but in my use case there are no identically configured VMs and i need to make sure it should be a highly available (HA) setup.

So as no identical VMs i am planning to go with Unmanaged instance group(for backend-service configuration in LB) but in gcp documentation it is mentioned that unmanaged instance group is not suitable for HA.

can you help me out which approach we need to choose for this use case?

Thanks in advance...

Answer 1

• Why are your VMs not identical?

If you put them in the same Unmanaged Instance Group, and then to an backend service the same request may end up in any of the VMs, so they need to serve the same content, for the same request.

• Can you give an example of your use case?

As in case you need more VMs to respond to the requests depending on the load for example, it is required to have a single image that can be provisioned on multiple VMs.

Another solution would be to have different backend services for each unique VM type, so that way every unique VM type would be in its own Managed Instance group.

I don't think there is another way, beside Managed Instance Group to achieve HA with VMs instances in GCP.