http负载均衡器和运行状况检查

Question

I found this question..

You want to configure autohealing for network load balancing for a group of Compute Engine instances that run in multiple zones, using the fewest possible steps. You need to configure recreation of VMs if they are unresponsive after 3 attempts of 10 seconds each. What should you do?

A. Create an HTTP load balancer with a backend configuration that references an existing instance group. Set the health check to healthy(HTTP)

B. Create an HTTP load balancer with a backend configuration that references an existing instance group. Define a balancing mode and set the maximum RPS to 10.

C. Create a managed instance group. Set the Autohealing health check to healthy(HTTP)

D. Create a managed instance group. Verify that the auto scaling setting is on.

Which is the correct answer? I think is A

Answer 1

You want to configure autohealing for network load balancing for a group of Compute Engine instances that run in multiple zones, using the fewest possible steps. You need to configure recreation of VMs if they are unresponsive after 3 attempts of 10 seconds each. What should you do?

Let's analyze each possible answer to determine the best answer. Note that this question has a key phrase "using the fewest possible steps". This phrase will bias selecting the best answer.

A. Create an HTTP load balancer with a backend configuration that references an existing instance group. Set the health check to healthy(HTTP)

This is a possible answer. This answer assumes that the existing backend is configured correctly.

B. Create an HTTP load balancer with a backend configuration that references an existing instance group. Define a balancing mode and set the maximum RPS to 10.

This is a possible answer. This answer assumes that the existing backend is configured correctly. This answer adds an additional step over answer A.

C. Create a managed instance group. Set the Autohealing health check to healthy(HTTP)

This is only a partial solution. The default configuration is auto scaling enabled. You still need to create the HTTP Load Balancer.

D. Create a managed instance group. Verify that the auto scaling setting is on.

This is only a partial solution. Creating a Managed Instance Group with Auto Scaling is required, but you still need to create the HTTP Load Balancer.

Drumroll Please ....

Therefore the best answer is A in my opinion.

Answer 2

To configure the recreation of VMs, you need Autohealing. So not B and D.

A: Load balancing health checks help direct traffic away from non-responsive instances and toward healthy instances; these health checks do not cause Compute Engine to recreate instances.

C: Application-based autohealing improves application availability by relying on a health checking signal that detects application-specific issues such as freezing, crashing, or overloading. If a health check determines that an application has failed on an instance, the group automatically recreates that instance .

So the answer is C .