Alibaba Cloud Certified Professional – Cloud Computing — Question 5
When using Alibaba Cloud SLB, a user configures the Health Check as follows: response time out value set to 5 seconds, Health Check interval set to 2 seconds, unhealthy threshold value set to 3, and healthy threshold value set to 3. That is to say, to confirm a backend ECS instance is healthy, three successive normal responses are required.
If the current status of a backend ECS instance is unhealthy, and you finish the repair work immediately. It will take at least _______________ for SLB Health Check to confirm this instance is healthy again.
Answer options
- A. 11 seconds
- B. 21 seconds
- C. 5 seconds
- D. 6 seconds
Correct answer: B
Explanation
The correct answer is B, 21 seconds. After the repair, the ECS instance needs to respond positively three times in a row to be considered healthy. Given the health check interval of 2 seconds, the first successful response occurs at 2 seconds, the second at 4 seconds, and the third at 6 seconds, totaling 18 seconds after the repair. Adding the initial 3 seconds for the unhealthy threshold means it takes at least 21 seconds to confirm health. The other options do not account for the necessary number of checks and their respective timings.