Getting Started

What It Does

  • Check current AWS resource usage against AWS Service Limits
  • Show and inspect current usage
  • Override default Service Limits (for accounts with increased limits)
  • Compare current usage to limits; return information about limits that exceed thresholds, and (CLI wrapper) exit non-0 if thresholds are exceeded
  • Define custom thresholds per-limit
  • Where possible, pull current limits from Trusted Advisor API
  • Supports explicitly setting the AWS region
  • Supports using STS to assume roles in other accounts, including using external_id.


An AWS Service or Product, such as EC2, VPC, RDS or ElastiCache. More specifically, Services in AwsLimitChecker correspond to distinct APIs for AWS Services.
An AWS-imposed maximum usage for a certain resource type in AWS. See AWS Service Limits. Limits are generally either account-wide or per-region. They have AWS global default values, but can be increased by AWS Support. “Limit” is also the term used within this documentation to describe AwsLimit objects, which describe a specific AWS Limit within this program.
“Usage” refers to your current usage of a specific resource that has a limit. Usage values/amounts (some integer or floating point number, such as number of VPCs or GB of IOPS-provisioned storage) are represented by instances of the AwsLimitUsage class. Limits that are measured as a subset of some “parent” resource, such as “Subnets per VPC” or “Read Replicas per Master” have their usage tracked per parent resource, so you can easily determine which ones are problematic.
The point at which AwsLimitChecker will consider the current usage for a limit to be problematic. Global thresholds default to usage >= 80% of limit for “warning” severity, and usage >= 99% of limit for “critical” severity. Limits which have reached or exceeded their threshold will be reported separately for warning and critical (we generally consider “warning” to be something that will require human intervention in the near future, and “critical” something that is an immediate problem, i.e. should block automated processes). The awslimitchecker command line wrapper can override the default global thresholds. The AwsLimitChecker class can both override global percentage thresholds, as well as specify per-limit thresholds as a percentage, a fixed usage value, or both.


  • Python 2.6 or 2.7 (boto currently has incomplete python3 support)
  • Python VirtualEnv and pip (recommended installation method; your OS/distribution should have packages for these)
  • boto


It’s recommended that you install into a virtual environment (virtualenv / venv). See the virtualenv usage documentation for more details, but the gist is as follows (the virtualenv name, “limitchecker” here, can be whatever you want):

virtualenv limitchecker
source limitchecker/bin/activate
pip install awslimitchecker


Aside from STS, awslimitchecker does nothing with AWS credentials, it leaves that to boto itself. You must either have your credentials configured in one of boto’s supported config files, or set as environment variables. See boto config and this project’s documentation for further information.

When using STS, you will need to specify the -r / --region option as well as the -A / --sts-account-id and -R / --sts-account-role options to specify the Account ID that you want to assume a role in, and the name of the role you want to assume. If an external ID is required, you can specify it with -E / --external-id.


To specify the region that awslimitchecker connects to, use the -r / --region command line option. At this time awslimitchecker can only connect to one region at a time; to check limits in multiple regions, simply run the script multiple times, once per region.

Required Permissions

You can view a sample IAM policy listing the permissions required for awslimitchecker to function properly either via the CLI client:

awslimitchecker --iam-policy

Or as a python dict:

from awslimitchecker.checker import AwsLimitChecker
c = AwsLimitChecker()
iam_policy = c.get_required_iam_policy()

You can also view the required permissions for the current version of awslimitchecker at Required IAM Permissions.