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Cloud Custodian - Policy Rules Engine

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**Table of Contents** - `Cloud Custodian <#cloud-custodian>`__ -
`Links <#links>`__ - `Usage <#usage>`__ - `Get
Involved <#get-involved>`__

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Cloud Custodian

Cloud Custodian is a rules engine for AWS resource management. It allows
users to define policies to be enforced to enable a well managed cloud,
with metrics and structured outputs. It consolidates many of the adhoc
scripts organizations have into a lightweight and flexible tool.

Organizations can use Custodian to manage their AWS environments by
ensuring compliance to security policies, tag policies, garbage
collection of unused resources, and cost management via off-hours
resource management.

Custodian policies are written in simple YAML configuration files that
specify given a resource type (ec2, asg, redshift, etc) and are
constructed from a vocabulary of filters and actions. Custodian was
created to unify the dozens of tools and scripts most organizations use
for managing their AWS accounts into one open source tool and provide
unified operations and reporting.

It integrates with lambda and cloudwatch events to provide for realtime
enforcement of policies with builtin provisioning on new resources or it
can be used to query and operate against all of account's extant


- `Docs <>`__
- `Developer
Install <>`__

Quick Install

.. code:: shell

$ virtualenv custodian
$ source custodian/bin/activate
$ pip install c7n


First a policy file needs to be created in yaml format, as an example:

.. code:: yaml

- name: remediate-extant-keys
description: |
Scan through all s3 buckets in an account and ensure all objects
are encrypted (default to AES256).
resource: s3
- encrypt-keys

- name: ec2-require-non-public-and-encrypted-volumes
resource: ec2
description: |
Provision a lambda and cloud watch event target
that looks at all new instances not in an autoscale group
and terminates those with unencrypted volumes.
type: cloudtrail
- RunInstances
- "tag:aws:autoscaling:groupName": absent
- type: ebs
key: Encrypted
value: false
- terminate

- name: tag-compliance
resource: ec2
Schedule a resource that does not meet tag compliance policies
to be stopped in four days.
- State.Name: running
- "tag:Environment": absent
- "tag:AppId": absent
- or:
- "tag:OwnerContact": absent
- "tag:DeptID": absent
- type: mark-for-op
op: stop
days: 4

Given that, you can run cloud-custodian

.. code:: shell

# Directory for outputs
$ mkdir out

# Validate the configuration
$ custodian validate -c policy.yml

# Dryrun on the policies (no actions executed)
$ custodian run --dryrun -c policy.yml -s out

# Run the policy
$ custodian run -c policy.yml -s out

Custodian supports a few other useful subcommands and options, including
outputs to s3, cloud watch metrics, sts role assumption.

Consult the documentation for additional information.

Get Involved

Mailing List -!forum/cloud-custodian

Gitter -


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“Project”). Any Contributor to the Project must accept and sign an
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the license granted in this Agreement to Capital One and to recipients
of software distributed by Capital One, You reserve all right, title,
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impact Your rights to use Your own Contributions for any other purpose

[Link to Agreement] (

This project adheres to the `Open Code of
Conduct <>`__. By participating,
you are expected to honor this code.

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