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Version: 3.2

Amazon CloudWatch Logs

Cribl LogStream supports sending data to Amazon CloudWatch Logs. This is a streaming Destination type. Cribl LogStream does not have to run on AWS in order to deliver data to CloudWatch Logs.

Configuring Cribl LogStream to Output to Amazon CloudWatch Logs

In the QuickConnect UI: Click + Add beside Destinations. From the resulting drawer's tiles, select CloudWatch Logs. Next, click either + Add New or (if displayed) Select Existing. The resulting drawer will provide the following options and fields.

Or, in the Data Routes UI: From the top nav of a LogStream instance or Group, select Data > Destinations. From the resulting page's tiles or the Destinations left nav, select CloudWatch Logs. Next, click + Add New to open a New Destination modal that provides the following options and fields.

General Settings

Output ID: Enter a unique name to identify this CloudWatch definition.

Log group name: CloudWatch log group to associate events with.

Log stream prefix: Prefix for CloudWatch log stream name. This prefix will be used to generate a unique log stream name per Cribl LogStream instance. (E.g., myStream_myHost_myOutputId.)

Region: AWS region where the CloudWatch Logs group is located.

Backpressure behavior: Select whether to block, drop, or queue events when all receivers are exerting backpressure. (Causes might include a broken or denied connection, or a rate limiter.) Defaults to Block.

Persistent Queue Settings

This section is displayed when the Backpressure behavior is set to Persistent Queue.

Max file size: The maximum size to store in each queue file before closing it. Enter a numeral with units of KB, MB, etc. Defaults to 1 MB.

Max queue size: The maximum amount of disk space the queue is allowed to consume. Once this limit is reached, queueing is stopped, and data blocking is applied. Enter a numeral with units of KB, MB, etc.

Queue file path: The location for the persistent queue files. This will be of the form: your/path/here/<worker-id>/<output-id>. Defaults to $CRIBL_HOME/state/queues.

Compression: Codec to use to compress the persisted data, once a file is closed. Defaults to None; Gzip is also available.

Queue-full behavior: Whether to block or drop events when the queue is exerting backpressure (because disk is low or at full capacity). Block is the same behavior as non-PQ blocking, corresponding to the Block option on the Backpressure behavior drop-down. Drop new data throws away incoming data, while leaving the contents of the PQ unchanged.


Use the Authentication Method buttons to select an AWS authentication method.

Auto: This default option uses the AWS instance's metadata service to automatically obtain short-lived credentials from the IAM role attached to an EC2 instance. The attached IAM role grants LogStream Workers access to authorized AWS resources. Can also use the environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY. Works only when running on AWS.

Manual: If not running on AWS, you can select this option to enter a static set of user-associated IAM credentials (your access key and secret key) directly or by reference. This is useful for Workers not in an AWS VPC, e.g., those running a private cloud. The Manual option exposes these corresponding additional fields:

  • Access key: Enter your AWS access key. If not present, will fall back to the env.AWS_ACCESS_KEY_ID environment variable, or to the metadata endpoint for IAM role credentials.

  • Secret key: Enter your AWS secret key. If not present, will fall back to the env.AWS_SECRET_ACCESS_KEY environment variable, or to the metadata endpoint for IAM credentials.

Secret: If not running on AWS, you can select this option to supply a stored secret that references an AWS access key and secret key. The Secret option exposes this additional field:

  • Secret key pair: Use the drop-down to select an API key/secret key pair that you've configured in LogStream's secrets manager. A Create link is available to store a new, reusable secret.

Assume Role

Enable for CloudWatch Logs: Toggle to Yes to use Assume Role credentials to access CloudWatch Logs.

AssumeRole ARN: Enter the Amazon Resource Name (ARN) of the role to assume.

External ID: Enter the External ID to use when assuming role.

Processing Settings


Pipeline: Pipeline to process data before sending the data out using this output.

System fields: A list of fields to automatically add to events that use this output. By default, includes cribl_pipe (identifying the LogStream Pipeline that processed the event). Supports wildcards. Other options include:

  • cribl_host – LogStream Node that processed the event.
  • cribl_wp – LogStream Worker Process that processed the event.
  • cribl_input – LogStream Source that processed the event.
  • cribl_output – LogStream Destination that processed the event.

Advanced Settings

Endpoint: CloudWatch Logs service endpoint. If empty, defaults to AWS' Region-specific endpoint. Otherwise, use this field to point to a CloudWatchLogs-compatible endpoint.

Signature version: Signature version to use for signing CloudWatch Logs requests. Defaults to v4.

Max queue size: Maximum number of queued batches before blocking. Defaults to 5.

Max record size (KB, uncompressed): Maximum size of each individual record before compression. For non-compressible data, 1MB (the default) is the maximum recommended size.

Flush period (sec): Maximum time between requests. Low settings could cause the payload size to be smaller than its configured maximum.

Reuse connections: Whether to reuse connections between requests. The default setting (Yes) can improve performance.

Reject unauthorized certificates: Whether to accept certificates that cannot be verified against a valid Certificate Authority (e.g., self-signed certificates). Defaults to Yes.

Environment: If you're using GitOps, optionally use this field to specify a single Git branch on which to enable this configuration. If empty, the config will be enabled everywhere.