Fix hub and spoke transitivity issues

[daniel-cit]

This PR Fixes some issues when enabling hub and spoke transitivity.

• reproduce error that happens in manual deploy in the integration build.
• add depends_on in the call to the transitivity module.
• Fix google_compute_region_instance_group_manager fixed max_surge_fixed for regional managed instance group issue
• Fix google_compute_region_instance_group_manager fixed max_unavailable_fixed for regional managed instance group issue

[daniel-cit]

Error that happens in manual apply of 3-networks shared reproduced in the integration build:

Step #12 - "converge-shared":        module.shared.module.base_transitivity[0].module.ilbs["us-west1"].data.google_compute_subnetwork.network: Refreshing state...
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        Error: Missing required argument
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.base_transitivity.ilbs/main.tf line 124, in resource "google_compute_firewall" "default-hc":
Step #12 - "converge-shared":         124:   network = data.google_compute_network.network.name
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        The argument "network" is required, but no definition was found.
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        Error: Missing required argument
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.base_transitivity.ilbs/main.tf line 124, in resource "google_compute_firewall" "default-hc":
Step #12 - "converge-shared":         124:   network = data.google_compute_network.network.name
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        The argument "network" is required, but no definition was found.
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        Error: Missing required argument
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.restricted_transitivity.ilbs/main.tf line 124, in resource "google_compute_firewall" "default-hc":
Step #12 - "converge-shared":         124:   network = data.google_compute_network.network.name
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        The argument "network" is required, but no definition was found.
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        Error: Missing required argument
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.restricted_transitivity.ilbs/main.tf line 124, in resource "google_compute_firewall" "default-hc":
Step #12 - "converge-shared":         124:   network = data.google_compute_network.network.name
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        The argument "network" is required, but no definition was found.
Step #12 - "converge-shared":        

[daniel-cit]

After fixing the dependency error we got:

       
       Error: Error creating RegionInstanceGroupManager: googleapi: Error 400: Invalid value for field 'resource.updatePolicy.maxSurge.fixed': '3'. Fixed updatePolicy.maxSurge for regional managed instance group has to be either 0 or at least equal to the number of zones., invalid
       
         on .terraform/modules/shared.base_transitivity.migs/modules/mig/main.tf line 36, in resource "google_compute_region_instance_group_manager" "mig":
         36: resource "google_compute_region_instance_group_manager" "mig" {
       
       
       
       Error: Error creating RegionInstanceGroupManager: googleapi: Error 400: Invalid value for field 'resource.updatePolicy.maxSurge.fixed': '3'. Fixed updatePolicy.maxSurge for regional managed instance group has to be either 0 or at least equal to the number of zones., invalid
       
         on .terraform/modules/shared.restricted_transitivity.migs/modules/mig/main.tf line 36, in resource "google_compute_region_instance_group_manager" "mig":
         36: resource "google_compute_region_instance_group_manager" "mig" {

This error happens because max_surge_fixed has a fixed value of 3

terraform-example-foundation/3-networks/modules/transitivity/main.tf

Line 65 in dd28deb

max_surge_fixed = 3

and one of the regions used, us-central1, has 4 zones to be used as distribution policy zones.

As of 2021-04-15 The fixed value of 3 for the max_surge_fixed will fail for regions europe-west1 and us-central1 which have four zones each.

[daniel-cit]

After fixing the max_surge_fixed issue we got the same problem with max_unavailable_fixed:

terraform-example-foundation/3-networks/modules/transitivity/main.tf

Line 68 in dd28deb

max_unavailable_fixed = 3

Step #12 - "converge-shared":        Error: Error creating RegionInstanceGroupManager: googleapi: Error 400: Invalid value for field 'resource.updatePolicy.maxUnavailable.fixed': '3'. Fixed updatePolicy.maxUnavailable for regional managed instance group has to be either 0 or at least equal to the number of zones., invalid
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.base_transitivity.migs/modules/mig/main.tf line 36, in resource "google_compute_region_instance_group_manager" "mig":
Step #12 - "converge-shared":          36: resource "google_compute_region_instance_group_manager" "mig" {
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        
Step #12 - "converge-shared":        Error: Error creating RegionInstanceGroupManager: googleapi: Error 400: Invalid value for field 'resource.updatePolicy.maxUnavailable.fixed': '3'. Fixed updatePolicy.maxUnavailable for regional managed instance group has to be either 0 or at least equal to the number of zones., invalid
Step #12 - "converge-shared":        
Step #12 - "converge-shared":          on .terraform/modules/shared.restricted_transitivity.migs/modules/mig/main.tf line 36, in resource "google_compute_region_instance_group_manager" "mig":
Step #12 - "converge-shared":          36: resource "google_compute_region_instance_group_manager" "mig" {

[bharathkkb]

LGTM
/cc @drebes