Working with Auto Scaling Groups

Working with Auto Scaling Groups


The Auto Scaling Groups (ASG) tab displays optimization opportunities for AWS Auto Scaling groups discovered through CloudWatch data collection. Optimization opportunities include group sizing and instance type recommendations based on predictive workload analytics.

To learn more watch the following video:

When working with ASGs, note the following:

  • EC2 instances that belong to an ASG are logically treated as part of the ASG service entity and recommendations are made for the group and not for the individual instances.
  • Auto Scaling groups configured with maximum group size = 1, are only included in the EC2 tab; ASGs configured with maximum group size > 1, are included in the Auto Scaling Groups tab.
  • ASGs configured to use the 'Combined Purchasing Options and Instance Types' feature will have an attached policy that defines the mix of instance types on which the ASG can run. Densify cannot analyze these ASGs. However, an ASG with a mixed policy attached, can still be configured to run on one instance type. These ASGs can be analyzed. Densify parses the mixed policy, attached to the ASG to determine if the ASG is actually configured to run a mix of instance types or on a single instance type.

The ASG optimization opportunity report is divided into two sections: 

  • A tabular report in the upper pane, shows details of the ASGs and their recommendations.
  • Tabs in the lower pane display the selected ASG's predicted scaling activity and resource utilization details. A third tab shows the effort required to implement the recommendations.

Data Controls

The controls, in the upper right corner of the page, provide options for managing and viewing your data more effectively.



Allows you to search for any type of data in the displayed columns. i.e. for a specific account or ASG. Typically, you will search for items in the first column, but you can search for a value in any column.

Click the icon and enter your search string. All matching rows are displayed in the table. You must enter a string of alpha-numeric characters. Wildcards are not supported.

If there are multiple pages, all pages are searched for the matching string.

Click this icon to export the content of the currently displayed table to .CSV format.

Click this icon to configure the table to display only the columns of interest. The default settings are re-applied when you navigate away from this page.

If there are more than 30 rows in this table, multiple pages will be indicated here. Click the right/left arrows to move to the next/previous page of a multi-page report.

You will see a vertical scroll bar if all 30 rows cannot be displayed.

Sorting Tabular Data

By default the table is sorted by Efficiency Rating. This is still the case even if you select another Group By option. You can sort the content of this table using any of the available columns, by clicking the column header.

  1. Click the column header to sort the table, in ascending order, using the content of the selected table as the sort key.
  2. Click the column header again, to sort the table, in descending order, again using the content of the selected table as the sort key.
  3. Click the column header a third time to clear the sort and return to the default, sorted by Efficiency Rating.
  4. An up/down arrow is displayed in the column header to indicate the column is being used to sort the content of the table.

Sorting is not persistent between pages or login sessions and this feature is only available on the Data tab.

ASG Tabular Report Sorting

The ASG tabular report is ordered based on the following sorting keys:

Table: ASG Sort Key Priority

Sort Key


1. Overall Status

The Auto scaling groups are first sorted by Overall Status, in the following order:

  1. Savings Opportunity
  2. Optimal
  3. Identified Risk

2. Optimization Type

If the Overall Status is the same, then the secondary sort key is Optimization Type. ASGs are sorted by Optimization Type in the following order:

  1. Terminate
  2. Modernize
  3. Modernize - Optimal Family
  4. Downscale
  5. Downsize
  6. Downsize - Optimal Family
  7. Just Right
  8. Upscale
  9. Upsize
  10. Upsize - Optimal Family

3. Account

If Overall Status and Optimization Types are the same for the ASGs, then the tertiary sort key is the Account number, in ascending order.

4. Auto Scaling Group name

If all of the above sort keys are the same, then the final sorting is done by the Auto Scaling group name, in ascending, alphabetical order.

Filtering by Recommendation

You can filter the ASG optimization tabular report based on recommendations using the Recommendation Filter Menu. This filter allows you to narrow the results of your report based on overall status, optimization type, effort required and whether or not the recommendation should be deferred. For details, see Using the Recommendation Filter Menu.

Tabular Data

The tabular report displays the current and recommended instance sizing and cost details for each ASG associated with downsizing, upsizing, or modernizing the instance type in the ASG's configuration. See the recommended Current Instance Type column for instance sizing recommendations.

The report also displays recommended group sizing associated with downscaling or upscaling the ASG. See the Current Minimum Size or the Current Maximum Size columns for the recommended group size. Refer to Reviewing the ASG Optimization Opportunity Report Columns for a description of the ASG tabular report columns.

Additional Tabs

The bottom pane of the ASG report provides the following information for the ASG, selected in the tabular report:

  • Predicted Scaling Activity—Shows workload charts for current and recommended predicted scaling activities for the selected ASG. For ASGs identified as "Just Right" or "Terminate" (optimization type), only the current in-service auto scaling activity chart is displayed.
  • Resource Utilization Metrics: ASG—Shows charts for current and recommended CPU Utilization, Memory Utilization for the selected ASG. Network I/O, Disk I/O workload charts are also included, showing utilization at the ASG level. For ASGs belonging to ECS clusters, additional CPU and Memory Reservation charts are displayed. You can view workload charts for each group member from the ASG In-Service Instance Details Page page.
  • Effort Details Tab—This table lists the factors that contribute to the effort required to investigate and implement the Densify recommendations. Effort for each group is calculated by rule-driven analytics based on factors (such as instance family change, data quality checks, feature changes, etc.) that can be configured in the policy settings and through analysis rule sets. A description of each rule and its impact on the effort to implement the recommended changes are provided.

Reviewing the ASG Optimization Opportunity Report Columns

Table: ASG Optimization Opportunity Report Columns

Column Name



The AWS linked account containing the Auto Scaling group.


The region containing the Auto Scaling group.

Auto Scaling Group

The AWS EC2 Auto Scaling group name, discovered from data collection.

The Auto Scaling group name is a hyperlink that opens the Impact Analysis and Recommendations report, from which you can review group-specific details. See Viewing the Public Cloud Impact Analysis and Recommendation Report.

ECS/EKS Reference

The ECS or EKS cluster associated with the Auto Scaling group. The additional cluster-level information is used for enhanced ASG analysis, resulting in more accurate recommendations.

The ECS reference is to the ECS cluster and for EKS, the reference is to the Kubernetes node group or cluster.

Note: This column is visible only if the Auto Scaling group uses an ECS or an EKS cluster.

When the ASG is associated with a Kubernetes cluster the Densify analysis requires additional information to ensure the ASG can satisfy all of the container reservation requests. If an ASG does not have an ECS/EKS Reference, or if this column is not visible, then additional data should be collected by deploying the Densify data forwarder into this cluster. Contact [email protected] for details.

Life Cycle

This is the instance market option configured for the Auto Scaling group.

  • Normal—The ASG is configured to run with On-Demand instances.
  • Spot—The ASG is configured to run with Spot instances.

Overall Status

Identifies the overall status of the optimization results based on Optimization Type and potential Net Savings ($/Month) :


These instance types are currently sized correctly and there are no costs savings for this group of systems.

Identified Risk

These instance types are at risk. This status occurs when the savings amount is less than $0 (i.e. you need to spend money to mitigate risk).

Identified Risk status is also indicated when the savings amount is $0, but optimization type is upscale, upsize, or upsize to optimal family. This situation occurs when services are inactive, however, they will need to be upscaled or upsized to mitigate risk when they resume activity.

Savings Opportunity

These instance types can provide saving opportunities that greater than $0.

Savings opportunity status is also indicated when the savings amount is $0, but optimization type is terminate, modernize, modernize to optimal family, downscale, downsize, or downsize to optimal family. This situation occurs when services are inactive, but have a recommendation of terminate, modernize, downsize or downscale when they resume activity to save money.

Optimization Type

The recommended action for the group of instances. See Optimization Type Descriptions and Color-Coding for a description of each recommendation.

Current Instance Type

Based on the data collected, the current catalog instances is listed.

Current Minimum Size

The minimum number of instances currently configured in the scale group.

Current Maximum Size

The maximum number of instances currently configured in the scale group.

Recommended Instance Type

Based on optimization analysis, the recommended catalog instances is listed.

Recommended Minimum Size

The minimum number of instances recommended for the scale group.

Recommended Maximum Group Size

The maximum number of instances recommended for the scale group.

Defer Recommendation

Defer recommendations until reserved instance coverage for this group expires. Values include:

  • Yes—defer recommendations due to RI coverage;
  • No—do not defer recommendations; this is also the case for "Terminate" recommendations;
  • "-" —not applicable; no change is listed for "Just Right" recommendations.

This field is based on AWS Defer Recommendation settings. Contact [email protected] to review your AWS Defer Recommendation settings.

Instances covered by a reserved instance should not be modified to the recommended instance type, since savings are already provided by the RI. When the applicable RI coverage expires, the instance can then be changed to the recommended instance type. Click the link in the Auto Scaling Group column to open the Impact Analysis and Recommendations report, for details.

Current Predicted Avg. Size

The average instance count for the ASG, based on the current utilization.

Recommended Predicted Avg. Size

The recommended predicted average instance count is determined by the upscale or downscale recommendation from the Densify analysis.

Net Savings ($/Month)

The estimated cost savings per month. The predicted average instance counts and the instance type cost are used to calculate the current and recommended estimated cost (i.e. estimated cost = per instance cost * predicted average instance count). The savings are calculated as the current estimated cost minus the recommended estimated cost.

In Service Instances

The number of instances currently running in the ASG. This value is the number of instances running at the time of the last data collection audit and is not representative of the entire day.

The value is a hyperlink that opens the ASG In-Service Instance Details Page page for the selected ASG.



This column describes the effort required to investigate and implement the Densify recommendations. The displayed group effort is an average of all the calculated efforts for each instance (or service) in the group. Effort for each instance is calculated by rule-driven analytics based on factors (such as family change, storage change, data quality checks, feature changes, etc.) that can be configured in the policy settings and rule set which captures best practices.

See the Effort Details tab in the lower pane for additional effort details for the selected ASG.

Total Savings ($/Month)

Total savings based on making all of the recommended changes. This is the sum of all net monthly savings. If the number of ASGs spans multiple pages this is the total for all pages.

ASG In-Service Instance Details Page

The ASG In Service Instance Details page is also divided into two panes:

  • The top pane contains a tabular report listing details of each in-service EC2 instance that is created from a launch template or configuration associated with the ASG, selected on the previous page. The running EC2 instances displayed, here are a snapshot from the last audit.
  • The bottom pane contains the resource utilization metrics for the in-service, EC2 instance, selected in the top pane. The tab includes charts for CPU Utilization, Memory Utilization, Network I/O, Disk I/O).
  • Note: If no metrics are available, then the corresponding chart is not displayed.

    These workload charts show hourly min/max and sustained activity for the selected system. Use the left/right arrows to scroll though the various workload charts.

Click the Back () button, in the top-right corner of the page, to return to the parent dashboard. Do not use the browser's Back button for navigation within Densify. You will be logged out of your session.

If ASG metrics data collection has not been enabled, the number of in-service instances is determined from the sample count value for any valid ASG EC2 metric such as %CPU utilization. For example, if we know that each instance is sampled 5 times within the sample interval (5 min), then if there are 10 samples, we know that there are 2 instances. If there are 50 samples then there are 10 instances, and so on. This in-service count is then loaded into the ASG In-Service Instances workload type.

Exporting the ASG Optimization Opportunity Report

  1. Click the download CSV icon to can export the content of the Auto Scaling Group dashboard to a .CSV file.
  2. The AutoScalingGroupsSummary report contains the tabular list of ASGs from the Auto Scaling Group optimization opportunity tabular list view. All filtering options will be applied to the exported data

  3. From the drill-down ASG In Service Instance Details report, click the Export to Excel icon at the top-right corner to export a file in Microsoft® Excel format, with the following sheet:
  4. The AsgServiceInstance report contains the launch configuration or template, instance type, minimum/maximum group size and a list of the in-service instances which correspond to the selected ASG In Service Instance Details report.

EKS-aware ASG Recommendations

ASGs and their EC2 group members are loaded from AWS audits and Kubernetes entities are collected via the Densify Data Forwarder from Prometheus data. Linking these entities is extremely complex as even the Kubernetes cluster names may not match.

A single Kubernetes cluster can run on or more ASGs with each ASG running in a node group within the cluster; however it is possible to skip node groups, and in this case the ASG must be linked directly to the cluster entity.

Densify matches, counts and links entities and ASG recommendations are made based on the established EKS or ECS-ASG associations.