Cloudwatch Retention

Our lambdas dump logs to AWS CloudWatch. By default, these logs exist indefinitely. However, there are ways to specify a duration for log retention.

aws-cli

In addition to getting your aws-cli set-up, there are two values you'll need to acquire.

1. log-group-name: the name of the log group who's retention policy (retention time) you'd like to change. We'll use /aws/lambda/KinesisInboundLogger in our examples.
2. retention-in-days: the number of days you'd like to retain the logs in the specified log group for. There is a list of possible values available in the aws logs documentation.

For example, if we wanted to set log retention to 30 days on our KinesisInboundLogger lambda, we would write:

aws logs put-retention-policy --log-group-name "/aws/lambda/KinesisInboundLogger" --retention-in-days 30

Note: The aws-cli log command that we're using is explained in detail here.

AWS Management Console

Changing the log retention policy in the AWS Management Console is a fairly simple process:

1. Navigate to the CloudWatch service in the AWS Management Console.
2. Click on the Logs entry on the sidebar.
3. Find the Log Group who's retention policy you're interested in changing.
4. Click on the value in the Expire Events After column.
5. Enter/Select the number of days you'd like to retain logs in that log group for.