Exam Professional Cloud Architect topic 1 question 9 discussion

"A" and "B" wouldn't turn the VMs on or off, it would jsut prevent traffic. "C" would turn them off if the health check is configured to terminate the VM is it fails. "D" is the start of a pseudo health check without any logic, so it also isn't an answer because it is like "A" and "B". Correct Answer: "C"

A. Ensure that a firewall rules exists to allow source traffic on HTTP/HTTPS to reach the load balancer. >> not correct, load balancer is not the issue here. B. Assign a public IP to each instance and configure a firewall rule to allow the load balancer to reach the instance public IP. >> defeats the purpose of getting load balancers , not correct C. Ensure that a firewall rule exists to allow load balancer health checks to reach the instances in the instance group.>> Correct. if using different port then appropriate FW rule need to be setup to ensure LB can reach backend instances for healthcheck. if healthcheck traffic is blcked, instances will be marked unhealthy and will be restarted. D. Create a tag on each instance with the name of the load balancer. Configure a firewall rule with the name of the load balancer as the source and the instance tag as the destination.>> tagging is not useful here as the instance is not the source of traffic, just the port need to be opened on FW.

The only answer which deals with the problem of the frequent stop / start of instances in a MIG.

C is correct because health check failures lead to a VM being marked unhealthy and can result in termination if the health check continues to fail. Because you have already verified that the instances are functioning properly, the next step would be to determine why the health check is continuously failing.

1. Health Checks are Essential: Load balancers rely on health checks to determine if instances in the backend pool are healthy and able to serve traffic. If the health checks fail, the load balancer assumes the instance is unhealthy and terminates it, leading to the constant cycling you're observing. 2. Firewall Rules for Health Checks: Even though your instances don't have public IPs, the load balancer needs to communicate with them through internal IPs for health checks. Firewall rules must be configured to allow this communication. 3. How Health Checks Work: The load balancer sends requests (e.g., HTTP, HTTPS, TCP) to the instances on a specific port and expects a certain response. The firewall needs to allow these requests to reach the instances and the responses to return to the load balancer.

c is right

C is correct

Most likely the problem of instances terminating is with the threshold settings on the health check. It’s thinking too sooner that some VMs can be terminated due to less load.

One thing that i couldn't understand is - How VMs getting terminated and relaunched for not setting health-checks in the load balancer ? how will that affect VM's uptime ?

If the healthcheck is not successful, it will keep on re-creating the instances in MIG.

C (LB Health check should be taken care of)

C is the correct answer

C. Ensure that a firewall rule exists to allow load balancer health checks to reach the instances in the instance group.

answer C: https://cloud.google.com/load-balancing/docs/health-check-concepts#ip-ranges

C is corect.

C is corect.

C is the correct answer.