Exam Professional Cloud Architect topic 1 question 52 discussion

Groups are better for management that non-groups so A and B are eliminated. Keeping the the instances in the same project will help maintain consistency, so C is better than D.

Yes, but why not choose a cost-effective solution like A, preferring a not required performance optimization solution like C? The question it's just asking for a simple fail over

Now you can use regional load balancer to route traffic to instance groups in different GCP projects. Welcome to cloud :-) https://cloud.google.com/blog/products/networking/cloud-load-balancing-gets-cross-project-service-referencing

C is correct

To set up a load balancer with a Compute Engine backend, your VMs need to be in an instance group. The managed instance group provides VMs running the backend servers of an external HTTP load balancer Therefore C

Why can't this be A since there is no mention of scaling?

Google recommend using MIG for Zonal outage and multiple MIG for regional outage https://cloud.google.com/architecture/disaster-recovery#compute-engine sentence says: Compute Engine instances are zonal resources, so in the event of a zone outage instances are unavailable by default. Compute Engine does offer managed instance groups (MIGs) which can automatically scale up additional VMs from pre-configured instance templates, both within a single zone and across multiple zones within a region. MIGs are ideal for applications that require resilience to zone loss and are stateless, but require configuration and resource planning. Multiple regional MIGs can be used to achieve region outage resilience for stateless applications.

MIG , in 1 project

the only solution that they want is to address regional outage. scalability or performance is not a concern at this point. MIG is better but that not what is solving the regional outage.

The correct answer is D: Deploy the application on two Compute Engine instance groups, each in a separate project and a different region. Use the first instance group to serve traffic, and use the HTTP load balancing service to fail over to the standby instance group in case of a disaster. To implement a disaster recovery plan that requires your application to fail over to another region in case of a regional outage, you should deploy the application on two Compute Engine instance groups, each in a separate project and a different region. This will ensure that the application is running in at least two regions, so that if one region experiences an outage, the application can still be accessed from the other region. You can use the HTTP load balancing service to distribute traffic between the two instance groups and to fail over to the standby instance group in case of a disaster. This will ensure that your application is always available, even in the event of a regional outage.

IMHO A would also work (test env). In production relying on instances from other regions (introducing latency) just for possible expected zonal outages, would not be my best practice.

Correct answer is C. No need to host MIG in separate projects.

ok for C

C is right choice

C - using instance groups when planning for DR is better than having single vm's (https://cloud.google.com/architecture/disaster-recovery). Having the resources in the same project is probably good for resource management.

Answer should have been A as autoscaling requirements are not mentioned.

I think you need an group for the load balancer so A no good?