AWS Auto Scaling Test

Amazon EC2 Auto Scaling helps you ensure that you have the correct number of Amazon EC2 instances available to handle the load for your application. You create collections of EC2 instances, called Auto Scaling groups. You can specify the minimum number of instances in each Auto Scaling group, and Auto Scaling ensures that your group never goes below this size. You can specify the maximum number of instances in each Auto Scaling group, and Auto Scaling ensures that your group never goes above this size. If you specify the desired capacity, either when you create the group or at any time thereafter, Auto Scaling ensures that your group has this many instances. If you specify scaling policies, then Auto Scaling can launch or terminate instances as demand on your application increases or decreases.

To measure the effectiveness of Auto Scaling, administrators should continuously track the size and state of instances in each Auto Scaling group and determine whether/not the groups automatically expand and shrink in size when the configured thresholds are breached. The AWS Auto Scaling test makes this evaluation possible!

For each Auto Scaling group, this test reports the minimum and maximum size threshold configured for that group and also the desired capacity specified for the group. Additionally, the test reveals the current number of instances in that group. By comparing the capacity thresholds with the current number of instances, administrators can tell whether/not Auto Scaling is successful in automatically resizing the group based on the demand/configuration. As an Auto Scaling group shrinks and expands automatically, the instances in the group pass through various states - pending state, standby state, terminating state, etc. With the help of this test, administrators can track the state of instances in each group.

Target of the test: Amazon EC2 Cloud

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each Auto Scaling group

First-level descriptor: AWS Region

Second-level descriptor: Auto Scaling group name

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The host for which the test is to be configured.

AWS Access Key, AWS Secret Key, Confirm AWS Access Key, Confirm AWS Secret Key

To monitor an Amazon EC2 instance, the eG agent has to be configured with the access key and secret key of a user with a valid AWS account. For this purpose, we recommend that you create a special user on the AWS cloud, obtain the access and secret keys of this user, and configure this test with these keys. The procedure for this has been detailed in the Obtaining an Access key and Secret key topic. Make sure you reconfirm the access and secret keys you provide here by retyping it in the corresponding Confirm text boxes.

Proxy Host and Proxy Port

In some environments, all communication with the AWS EC2 cloud and its regions could be routed through a proxy server. In such environments, you should make sure that the eG agent connects to the cloud via the proxy server and collects metrics. To enable metrics collection via a proxy, specify the IP address of the proxy server and the port at which the server listens against the Proxy Host and Proxy Port parameters. By default, these parameters are set to none , indicating that the eG agent is not configured to communicate via a proxy, by default.

Proxy User Name, Proxy Password, and Confirm Password

If the proxy server requires authentication, then, specify a valid proxy user name and password in the Proxy User Name and Proxy Password parameters, respectively. Then, confirm the password by retyping it in the Confirm Password text box. By default, these parameters are set to none, indicating that the proxy sever does not require authentication by default.

Proxy Domain and Proxy Workstation

If a Windows NTLM proxy is to be configured for use, then additionally, you will have to configure the Windows domain name and the Windows workstation name required for the same against the Proxy Domain and Proxy Workstation parameters. If the environment does not support a Windows NTLM proxy, set these parameters to none.

Exclude Region

Here, you can provide a comma-separated list of region names or patterns of region names that you do not want to monitor. For instance, to exclude regions with names that contain 'east' and 'west' from monitoring, your specification should be: *east*,*west*

Measurements made by the test

Measurement

Description

Measurement Unit

Interpretation

Minimum instances in group

Indicates the minimum size of this group.

Number

Maximum instances in group

Indicates the maximum size of this group.

Number

Desired capacity of group

Indicates the number of instances that this group attempts to maintain.

Number

Running instances in group

Indicates the number of instances in currently running in this group.

Number

This measure represents the number of instances that are currently in the 'InService' state.

When Auto Scaling responds to a scale out event, it launches one or more instances. When the instances are fully configured, they are attached to the Auto Scaling group and they enter the InService state

Instances remain in the InService state until one of the following occurs:

  • A scale in event occurs, and Auto Scaling chooses to terminate this instance in order to reduce the size of the Auto Scaling group.
  • You put the instance into a Standby state.
  • You detach the instance from the Auto Scaling group.
  • The instance fails a required number of health checks, so it is removed from the Auto Scaling group, terminated, and replaced.

This metric does not include instances that are pending or terminating.

Pending state instances in group

Indicates the number of instances in this group that are in the Pending state.

Number

When a scale out event occurs, the Auto Scaling group launches the required number of EC2 instances, using its assigned launch configuration. These instances start in the Pending state. pending instance is not yet in service.

This metric does not include instances that are in service or terminating.

Standby state instances in group

Indicates the number of instances in this group that are in the Standby state.

Number

Instances in the Standby state are still running but are not actively in service.

Terminating state instances

Indicates the number of instances in this group that are in the Terminating state.

Number

When Auto Scaling responds to a scale in event, it terminates one or more instances. These instances are detached from the Auto Scaling group and enter the Terminating state.

This metric does not include instances that are in service or pending.

Total instances in group

Indicates the total number of instances in this group.

Number

This metric identifies the number of instances that are in running, pending, and terminating states.