c7n-log-exporter: Cloud watch log exporter automation

A small serverless app to archive cloud logs across accounts to an archive bucket. It utilizes cloud log export to s3 feature for historical exports.

It also supports kinesis streams / firehose to move to realtime exports in the same format as the periodic historical exports.

Features

Log group filtering by regex
Incremental support based on previously synced dates
Incremental support based on last log group write time
Cross account via sts role assume
Lambda and CLI support.
Day based log segmentation (output keys look like $prefix/$account_id/$group/$year/$month/$day/$export_task_uuid/$stream/$log)

Assumptions

The archive bucket has already has appropriate bucket policy permissions. For details see: https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/S3ExportTasks.html#S3Permissions
Default periodicity for log group archival into s3 is daily.
Exporter is run with account credentials that have access to the archive s3 bucket.
Catch up archiving is not run in lambda (do a cli run first)

Cli usage

make install

You can run on a single account / log group via the export subcommand

c7n-log-exporter export --help

Config format

To ease usage when running across multiple accounts, a config file can be specified, as an example.

Using S3 Bucket as destination

destination:
  bucket: custodian-log-archive
  prefix: logs2

accounts:
  - name: custodian-demo
    role: "arn:aws:iam::111111111111:role/CloudCustodianRole"
    groups:
      - "/aws/lambda/*"
      - "vpc-flow-logs"

Using CloudWatch Destination as destination cross account

The Cloudwatch Destination needs setup in account and access policy set on CloudWatch Destination to to allow source account access to the Cloudwatch Destination

subscription:
  destination-arn: "arn:aws:logs:us-east-1:111111111111:destination:CustodianCWLogsDestination"
  destination-role: "arn:aws:iam::111111111111:role/CWLtoKinesisRole"
  name: "CustodianCWLogsDestination"

destination:
  bucket: custodian-log-archive
  prefix: logs2

accounts:
  - name: custodian-demo
    # https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CreateSubscriptionFilter-IAMrole.html
    subscription-role: "arn:aws:iam::111111111111:role/<role-name>"
    role: "arn:aws:iam::111111111111:role/CloudCustodianRole"
    groups:
      - "/aws/lambda/*"
      - "vpc-flow-logs"

Multiple accounts via cli

To run on the cli across multiple accounts, edit the config.yml to specify multiple accounts and log groups.

c7n-log-exporter run --config config.yml

Serverless Usage

Edit config.yml to specify the accounts, archive bucket, and log groups you want to use.

make install
make deploy