feat(autoscaling): add new check autoscaling_group_multiple_instance_types

[danibarranqueroo]

Context

This new check ensures that Amazon EC2 Auto Scaling groups use multiple instance types and deploy instances across multiple Availability Zones. Using multiple instance types enhances availability by allowing the Auto Scaling group to launch alternative instance types if there is insufficient capacity in the chosen Availability Zones, improving resilience and high availability.

I have done the check following this guide, but I have some concerns. While testing the check on real infrastructure, I realized that there are two ways to add instance types: either by adding a new instance attached to the Auto Scaling group or by adding a new override to the Launch Template to include new supported instance types.

Also, for the unit tests I needed to use botocore because moto does not cover the attach_instance api call.

Description

Added new check autoscaling_group_multiple_instance_types with its unit tests.

Checklist

• Are there new checks included in this PR? Yes / No
  • If so, do we need to update permissions for the provider? Please review this carefully.
• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.24%. Comparing base (bc1e6c0) to head (5a7636e).
Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5325      +/-   ##
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+ Coverage   89.18%   89.24%   +0.05%     
==========================================
  Files        1037     1044       +7     
  Lines       32004    32225     +221     
==========================================
+ Hits        28544    28760     +216     
- Misses       3460     3465       +5     

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[MrCloudSec]

Suggested change

	"CheckID": "autoscaling_group_multiple_instances_types_in_multiaz",
	"CheckID": "autoscaling_group_multiple_instance_types",

[MrCloudSec]

Can we check if an AZ has more than one instance types?
For example, if there are 2 AZs and in one there are multiple instance types but in the other one only one instance type, it should fail.

[danibarranqueroo]

Hi @sergargar!

These past few days, I’ve been working on other checks from this same service, and since they’re all merged now, I’ve finally made the changes you suggested. To do this, I needed to merge those checks into this branch and then start working on how to verify if each AZ has multiple instances. I decided to store each instance's AZ in a dictionary, using the AZ name as the key and the instance type as the value. During the check, I verify if each AZ has 2 or more values.

Since Moto still doesn’t support the attach_instances API call, I’ve kept the old describe_autoscaling_groups test, which covers the other Auto Scaling checks, and created a new test specifically for this Auto Scaling group with attached instances.

Hope this message helps you understand what I’ve done more quickly 🚀😄