Table of Contents
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 resources.
$ virtualenv custodian
$ source custodian/bin/activate
$ pip install c7n
First a policy file needs to be created in yaml format, as an example:
policies:
- name: remediate-extant-keys
description: |
Scan through all s3 buckets in an account and ensure all objects
are encrypted (default to AES256).
resource: s3
actions:
- 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.
mode:
type: cloudtrail
events:
- RunInstances
filters:
- "tag:aws:autoscaling:groupName": absent
- type: ebs
key: Encrypted
value: false
actions:
- terminate
- name: tag-compliance
resource: ec2
description:
Schedule a resource that does not meet tag compliance policies
to be stopped in four days.
filters:
- State.Name: running
- "tag:Environment": absent
- "tag:AppId": absent
- or:
- "tag:OwnerContact": absent
- "tag:DeptID": absent
actions:
- type: mark-for-op
op: stop
days: 4
Given that, you can run cloud-custodian
# 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.
Mailing List - https://groups.google.com/forum/#!forum/cloud-custodian
Gitter - https://gitter.im/capitalone/cloud-custodian
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