modules/mig replacement_method should default to SUBSTITUTE

[apeabody]

TL;DR

modules/mig replacement_method should default to SUBSTITUTE

https://cloud.google.com/compute/docs/instance-groups/rolling-out-updates-to-managed-instance-groups#replacement_method

Terraform Resources

No response

Detailed design

No response

Additional information

No response

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[bharathkkb]

@apeabody is SUBSTITUTE recommended by GCP?

[apeabody]

It is per https://cloud.google.com/compute/docs/instance-groups/rolling-out-updates-to-managed-instance-groups#replacement_method:

Valid replacementMethod values are:

SUBSTITUTE (default). Replaces VM instances faster during updates because new VMs are created before old ones are shut down. However, instance names aren't preserved because the names are still in use by the old instances.

RECREATE. Preserves instance names through an update. Compute Engine releases the instance name as the old VM is shut down. Then Compute Engine creates a new instance using that same name. To use this mode, you must set maxSurge to 0.