Prioritizing Rightsizing Recommendations

Prioritizing Rightsizing Recommendations

Now that you understand how AWS Cost Explorer Rightsizing recommendations work let’s run an example and find how to prioritize quick wins.

Download your Rightsizing Recommendations

1. Select Download CSV to download your Rightsizing recommendations report

Filter your Rightsizing Recommendations

Let’s filter out instances that are either too small or were only running for a few hours since the analysis was made. By doing so, we minimize the time required to perform rightsizing modifications that would otherwise result in minimal savings.

1. Insert a new column to the right of the Recommended Action column.

2. Name the new column’s first row “TooSmall” This will be the label for this new column

3. Paste the following formula in each row below the label

    =IF(X2<25,1,0)
   

Where Column X = Recommended Instance Type 1 Estimated Savings

This formula will flag with a “1” any instance that will fail to deliver more than $25/month in savings (or $300/year). Feel free to adjust the threshold for your organization own savings expectation. If you prefer to do the analysis based on specific instance sizes instead of potential savings you can use the following formula to exclude smaller instances from the recommendations as well.

    =IF(N2="Modify",IF(SUMPRODUCT(--(NOT(ISERR(SEARCH({"nano","micro","small","medium"},F2)))))>0,"1","0"),"0")

Where Column N = Recommended action and Column F = Instance Type

Flag your Rightsizing Recommendations

Now let’s flag EC2 instances that belong to old generations (C4, M3, etc).

Since you are investing engineer time on rightsizing let’s make sure you are also leveraging the newest technology available. Newer EC2 generations have a superior performance increasing the changes of success for the rightsizing exercise, they also generally cost less than previous generations providing a higher cost vs benefit.

1. Insert a new column to the right of the Instance Type column

2. Name the new column’s first row “OldGen” This will be the label for this new column

3. Paste the following formula in each row below the label

    =IF(SUMPRODUCT(--(NOT(ISERR(SEARCH({"t1","m1","c1","m2","i2","g2","c3","m3","r3","c4","m4","r4","cr1","hs1"},F2)))))>0,"1","0")
   

Column F = Instance Type

This formula will flag with a “1” instances from old generations.

Sort your recommendations by low complexity and higher savings

• Group 1: Idle EC2 resources

  • Filter the data on Recommended Action = “Terminate”
  • Sort the data by Recommended Instance Type 1 Estimated Savings = Largest to smallest
  • Start filtering the idle resources or instances where CPU utilization <1%, it is likely these instances were launched and forgotten so the potential savings might represent the entire cost of running that instance.

  

The resulting filtered list should be where you start rightsizing discussions with application owners. Perform an investigation to understand why these instance were launched in the first place and validate their usage with the resource owner. Don’t forget to review the column Total running hours to separate idle resources that were recently launched vs the ones who are running uninterruptedly over the past 14 days.

If you are using the rightsizing CSV file provided in this lab exercise, you will notice that we filtered down from an original 1,051 recommendations to 17 and identified $2,859 per month in potential savings. You will also find in the example some instances showing 0 estimated savings, that’s because they were running under Savings Plan (SP) or Reserved Instances (RI). On these cases AWS will not estimate savings, but if these instances can be terminated the committed SP/RI hours might float to On Demand usage within your account depending on the RI/SP scope .

• Group 2: Previous generation instances

  • Filter the data on Recommended Actions = “Modify” AND OldGen = “1” AND TooSmall = “0”
  • Sort the data by Recommended Instance Type 1 Estimated Savings = Largest to smallest

This list will focus on the underutilized resources (>1% CPU) that belongs to previous generations and can either be downsized within the same family (column P below) or modernized to the newest generation.

Moving to a new generation will require additional investment in the form of more testing hours compared to instances identified on Group 1, but depending on the case it can maximize savings and performance. Refer to the EC2 previous generation page for information on upgrade paths to current generation instance families.

If you are using the rightsizing CSV file provided in this lab exercise, you will notice that we filtered down from originally 1,051 recommendations to 15 with $7,089 per month in potential savings.

• Group 3: Current generation instances

  • Filter the data on Recommended Actions = “Modify” AND OldGen = “0” AND TooSmall = “0”
  • Sort the data by Recommended Instance Type 1 Estimated Savings = Largest to smallest

This will select underutilized resources from the current, most modern generation. We recommend sorting them by potential savings to make sure you are prioritizing the instances that will provide larger savings first.

Also, do not forget to check the other recommended instance types. Rightsizing recommendations will recommend up to 3 instances for each resource moving from a more conservative recommendation (the first recommendation) to a more aggressive and higher savings recommendation (second and third recommendations).

If you are using the rightsizing CSV file provided in this lab exercise, you will notice that we filtered down from originally 1,051 recommendations to 37 with $18,728 per month in potential savings.

Conclusions

During this lab exercise, we learned how to prioritize the rightsizing recommendations with the goal of identifying low complexity and high savings recommendations. We initially started with 1,051 recommendations with a potential saving of $29,603 but we managed to identify the top 69 cases with lowest complexity that together add up to $28,676 of the overall potential saving.

Group 1 (Idle) and Group 2 (Previous Generation) are the less complex cases where you may want to start the rightsizing exercises for your organization. As you gain more confidence and learn how to develop a regular process for rightsizing, your organization will be able to rapidly act on Group 3 (Current/modern generation) and other cases.