Your application currently leverages AWS Auto Scaling to grow and shrink as load Increases’
decreases and has been performing well Your marketing team expects a steady ramp up in traffic
to follow an upcoming campaign that will result in a 20x growth in traffic over 4 weeks Your
forecast for the approximate number of Amazon EC2 instances necessary to meet the peak
demand is 175.
What should you do to avoid potential service disruptions during the ramp up in traffic?
A.
Ensure that you have pre-allocated 175 Elastic IP addresses so that each server will be able to
obtain one as it launches
B.
Check the service limits in Trusted Advisor and adjust as necessary so the forecasted count
remains within limits.
C.
Change your Auto Scaling configuration to set a desired capacity of 175 prior to the launch of
the marketing campaign
D.
Pre-warm your Elastic Load Balancer to match the requests per second anticipated during peak
demand prior to the marketing campaign
20 X growth in 4 weeks so no need to pre warm Elastic load balancer. Ans should be Check Service limit.
B
0
0
D is the answer
0
0
D
0
0
b
0
0
b
0
0
It is B. It can’t be D because pre-warming of an ELB is for anticipated spikes which happen in minutes rather then the gradual change proposed in the question.
0
0
It is D, believe me, trusted advisor makes no sense in the equation. You are not required to respect the limits, and you can’t actually “adjust” anything there. Pre-warming is the right approach.
D, final answer.
0
0
D is incorrect in this scenario.
“In certain scenarios, such as when flash traffic is expected, or in the case where a load test cannot be configured to gradually increase traffic, we recommend that you contact us to have your load balancer “pre-warmed”.”
Pre-warming is only used when flash traffic is expected. In this question, the traffic increases over a 4 week period.
Answer B is the correct answer, as you need to ensure you don’t hit any service limits as the autoscaling group increases to the 175 predicted amount.
0
0
Pre-warming can handle the flash traffic, then definitely can handle gradually increase.
0
0
D
0
0
B
if you’re not able to provision 175 instances due to service limit constrictions you lose, it’s that simple.
0
0
Answer is D to pass certification
0
0
You have to take service limits into account when your organization is anticipating 175 instances to support the projected workload. Trusted Advisor Service Limit Check feature notifies you if your usage is more than 80% of the service limit.
Moreover, the question does not specify that the organization is using ELB (Just trying to be funny here :)). If you are expecting AutoScale to launch 175 instances, you would definitely want to have ELB in place.
0
0
B
If you don’t adjust service limits (aka EC2 20 VM limit) then it doesn’t matter if your ELB is pre-warmed. There are just tons and tons of service limits which would affect a quick ramp up: http://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html
The word “gradual” over 4 wks is the giveaway that it can’t be pre-warm. Here’s prewarm link:
https://aws.amazon.com/articles/1636185810492479
Amazon ELB is able to handle the vast majority of use cases for our customers without requiring “pre-warming” (configuring the load balancer to have the appropriate level of capacity based on expected traffic). In certain scenarios, such as when flash traffic is expected, or in the case where a load test cannot be configured to gradually increase traffic, we recommend that you contact us to have your load balancer “pre-warmed”. We will then configure the load balancer to have the appropriate level of capacity based on the traffic that you expect. We will need to know the start and end dates of your tests or expected flash traffic, the expected request rate per second and the total size of the typical request/response that you will be testing.
0
0
D is the answer
– When looking at https://aws.amazon.com/articles/1636185810492479#pre-warming
– The pre-warm does mention that a certain scenario would be flash traffic. It also mentions that a certain scenario would be when the ELB cannot gradually come in line with your expected traffic requirements. In this scenario, you are increasing your workload (possibly) by 5 times each week and the ELB may not be able to handle this.
– The reasonable response from the customer would be to pre-warm the ELB as it is the primary point for connections from the customer for high availability
– Also, if we look at the requirements for pre-warming an ELB, the scenario already gives us two of the requirements that need to be submitted to AWS for the pre-warm
B is a contender but let’s be clear that Trusted Advisor only lists limits for reserved instance purchases and not on-demand. If you want to check your EC2 on-demand limits you have to use the AWS console to check these limits. Like here: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-resource-limits.html
TA would be good to run if they had mentioned reserved instances in the question, etc.
0
0
Answer: D
Explanation:
Amazon ELB is able to handle the vast majority of use cases for our customers without requiring “pre-warming”
(configuring the load balancer to have the appropriate level of capacity based on expected traffic).
https://aws.amazon.com/articles/1636185810492479#pre-warming
0
0