Cribl Stream supports sending events to OpenTelemetry Protocol (OTLP)-compliant targets. (Cribl Stream can receive OTel events through the OTel Source.) Besides native OTel Trace, Metric, and Log events, you can send Cribl Stream’s Gauge metric events through this OTel Destination.

Type: Streaming | TLS Support: Configurable | PQ Support: Yes

Protocol and Transport Support ​

This Destination supports either of the transports that OTLP specifies: gRPC or HTTP. OTLP defines Protocol buffer (Protobuf) schemas for its payloads (requests and responses). With the HTTP transport, this Destination supports Binary Protobuf payload encoding, but does not support JSON Protobuf.

When configuring Pipelines (including pre-processing and post-processing Pipelines), you need to ensure that events sent to this Destination conform to the relevant Protobuf specification. Links below are for OTLP 1.3.1:

• For traces, opentelemetry/proto/trace/v1/trace.proto
• For metrics, opentelemetry/proto/metrics/v1/metrics.proto
• For logs, opentelemetry/proto/logs/v1/logs.proto

The OTel Destination will drop non-conforming events. If the Destination encounters a parsing error when trying to convert an event to OTLP, it discards the event and Cribl Stream logs the error.

If sending data to a downstream receiver that accepts OTLP 1.3.1 log events, you must select Advanced Settings > OTLP version > 1.3.1. Otherwise, the Destination will send log events formatted for OTLP 0.10.0. For context, see Breaking Changes Between OTLP 0.19.0 and 1.3.1.

Configure Cribl Stream to Output to OTel ​

1. On the top bar, select Products, and then select Cribl Stream. Under Worker Groups, select a Worker Group. Next, you have two options:
   • To configure via QuickConnect, navigate to Routing > QuickConnect (Stream) or Collect (Edge). Select Add Destination and select the Destination you want from the list, choosing either Select Existing or Add New.
   • To configure via the Routes, select Data > Destinations or More > Destinations (Edge). Select the Destination you want. Next, select Add Destination.
2. In the New Destination modal, configure the following under General Settings:

   • Output ID: Enter a unique name to identify this OTel output definition. If you clone this Destination, Cribl Stream will add -CLONE to the original Output ID.

   • Description: Optionally, enter a description.

   • OTLP version: The drop-down offers 0.10.0 (default) and 1.3.1.

   • Protocol: Use the drop-down to choose the protocol to use when sending data: gRPC (the default), or HTTP. Additional settings display in the Advanced for both gRPC and HTTP.

     
     When set to HTTP, the UI adds the Retries section (left tab) and displays three additional settings below:
     

   • Traces endpoint override: By default, the Destination will send traces to <endpoint>/v1/traces, where <endpoint> is what you specified for the Endpoint setting above. To send traces to a different endpoint, enter that endpoint here.

   • Metrics endpoint override: By default, the Destination will send metrics to <endpoint>/v1/metrics, where <endpoint> is what you specified for the Endpoint setting above. To send metrics to a different endpoint, enter that endpoint here.

   • Logs endpoint override: By default, the Destination will send logs to <endpoint>/v1/logs, where <endpoint> is what you specified for the Endpoint setting above. To send logs to a different endpoint, enter that endpoint here.

   • Endpoint: Where to send events, in any of a variety of formats (FQDN, PQDN, IP address and port, etc). Supports both IPv4 and IPv6 - IPv6 addresses must be enclosed in square brackets. The same endpoint is used for both Traces and Metrics. If no port is specified, we normally default to the standard port for OTel Collectors, 4137 - however, if TLS is enabled or the endpoint is an HTTPS-based URL, we default instead to port 443.

     To proxy outbound HTTP/S requests, see System Proxy Configuration.

   • Backpressure behavior: Whether to block, drop, or queue events when all receivers are exerting backpressure.

   • Tags: Optionally, add tags that you can use to filter and group Destinations on the Destinations page. These tags aren’t added to processed events. Use a tab or hard return between (arbitrary) tag names.

3. Optionally, you can adjust the Authentication, TLS, Persistent Queue, Processing, Retries, and Advanced settings outlined in the sections below.
4. Select Save, then Commit & Deploy.

Authentication ​

Select one of the following options for authentication:

• None: Don’t use authentication.

• Auth token: Enter the bearer token that must be included in the authorization header. Since OpenTelemetry runs over gRPC, authorization headers are sent as Metadata entries which are essentially key-value pairs. For example: Bearer <your-configured-token>.

• Auth token (text secret): This option exposes a drop-down in which you can select a stored text secret that references the bearer token described above. A Create link is available to store a new, reusable secret.

• Basic: This default option displays fields for you to enter HTTP Basic authentication credentials.

• Basic (credentials secret): This option exposes a Credentials secret drop-down, in which you can select a stored text secret that references the Basic authentication credentials described above. A Create link is available to store a new, reusable secret.

• OAuth (text secret): Configure authentication using the OAuth 2.0 Client Credentials flow. Available only when Protocol is set to HTTP. Selecting this option exposes additional fields - see OAuth Authentication.

OAuth Authentication ​

Selecting OAuth (text secret) for Authentication type exposes the following additional fields:

• Login URL: Endpoint for the OAuth token request, which is expected to be a POST call.

• OAuth secret: Select a stored text secret that holds the OAuth client secret parameter value to pass in the token request body. A Create link is available to store a new, reusable secret.

• OAuth secret parameter name: Parameter name for the secret value in the token request body.

• Token attribute name: Name of the auth token attribute in the OAuth response. Can be top-level (for example, token); or nested, using a period (for example, data.token).

• Authorize expression: JavaScript expression used to compute the Authorization header to pass in requests. Uses ${token} to reference the token obtained from the login POST request, for example: `Bearer ${token}`.

• Refresh interval (secs.): How often to refresh the OAuth token. Default 3600 seconds (1 hour); minimum 1 second; maximum 300000 seconds (about 83 hours).

• OAuth parameters: Optionally, select Add parameter for each additional parameter you want to send in the OAuth token request. Cribl Stream will combine the secret with these parameters, and will send the URL-encoded result in a POST request to the endpoint specified in Login URL. Cribl Stream automatically adds the Content-Type header application/x-www-form-urlencoded when sending this request.

  In each row of the resulting table, enter the parameter’s Name. The corresponding Value is a JavaScript expression to compute the parameter’s value. This can also evaluate to a constant. Values not formatted as expressions - for example, id instead of `${id}` - will be evaluated as strings.

• OAuth headers: Optionally, select Add Header for each custom header you want to send in the OAuth token request. Cribl Stream automatically adds the Content-Type header application/x-www-form-urlencoded when sending this request.

  In each row of the resulting table, enter the custom header’s Name. The corresponding Value is a JavaScript expression to compute the header’s value. This can also evaluate to a constant. Values not formatted as expressions - for example, id instead of `${id}` - will be evaluated as strings.

TLS Settings (Client Side) ​

TLS is available only when General Settings > Protocol is set to gRPC.

Enabled Default is toggled off. When toggled on:

Validate server certs: Toggle on (default) to reject certificates that are not authorized by a CA in the CA certificate path, nor by another trusted CA (for example, the system’s CA).

Minimum TLS version: Optionally, select the minimum TLS version to use when connecting.

Maximum TLS version: Optionally, select the maximum TLS version to use when connecting.

Certificate: Select an existing certificate name from the drop-down or add a new certificate by selecting Create. See Add a TLS Certificate to a Worker Group for details.

CA certificate path: Path on client containing CA certificates (in PEM format) to use to verify the server’s cert. Path can reference $ENV_VARS.

Private key path (mutual auth): Path on client containing the private key (in PEM format) to use. Path can reference $ENV_VARS. Use only if mutual auth is required.

Certificate path (mutual auth): Path on client containing certificates in (PEM format) to use. Path can reference $ENV_VARS. Use only if mutual auth is required.

Passphrase: Passphrase to use to decrypt private key.

Persistent Queue Settings ​

The Persistent Queue Settings tab displays when the Backpressure behavior option in General settings is set to Persistent Queue. Persistent queue buffers and preserves incoming events when a downstream Destination has an outage or experiences backpressure.

Before enabling persistent queue, learn more about persistent queue behavior and how to optimize it with your system:

• About Persistent Queues
• Optimize Destination Persistent Queues
• About Destination Backpressure Triggers

Some of these settings might not appear if you set the persistent queue storage mode to Network filesystem or AWS S3 at the Worker Group level (Worker Group Settings > PQ Storage). When using these storage types, this behavior is managed at the Worker Group level. See Worker Group PQ Storage Fields for more information.

On Cribl-managed Cloud Workers (with an Enterprise plan), this tab exposes only the destructive Clear Persistent Queue button (described at the end of this section). A maximum queue size of 1 GB disk space is automatically allocated per PQ-enabled Destination, per Worker Process. The 1 GB limit is on outbound uncompressed data, and no compression is applied to the queue.

This limit is not configurable. If the queue fills up, Cribl Stream/Edge will block outbound data. To configure the queue size, compression, queue-full fallback behavior, and other options below, use a hybrid Group.

Mode: Use this menu to select when Cribl Stream/Edge engages the persistent queue in response to backpressure events from this Destination. The options are:

If a Worker/Edge Node starts with an invalid Mode setting, it automatically switches to Error mode. This might happen if the Worker/Edge Node is running a version that does not support other modes (older than 4.9.0), or if it encounters a nonexistent value in YAML configuration files.

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

Queue size limit: The maximum amount of disk space that the queue can consume on each Worker Process. When the queue reaches this limit, the Destination stops queueing data and applies the Queue-full behavior. Defaults to 5 GB. This field accepts positive numbers with units of KB, MB, GB, and so on. You can set it as high as 1 TB, unless you’ve configured a different Worker Process PQ size limit on the Worker Group/Fleet Settings page.

Queue file path: The location for the persistent queue files. Defaults to $CRIBL_HOME/state/queues. Cribl Stream/Edge will append /<worker-id>/<output-id> to this value.

Compression: Set the codec to use when compressing the persisted data after closing a file. Defaults to None. Gzip is also available.

Queue-full behavior: Whether to block or drop events when the queue begins to exert backpressure. A queue begins to exert backpressure when the disk is low or at full capacity. This setting has two options:

• Block: The output will refuse to accept new data until the receiver is ready. The system will return block signals back to the sender.
• Drop new data: Discard all new events until the backpressure event has resolved and the receiver is ready.

Buffer size limit (bytes): The maximum memory to buffer events before flushing them to persistent queue on disk. Enter a value with a unit suffix. For example: 64KB, 128KB, or 1MB. Spaces between the number and unit are allowed (such as 64 KB). Units are case-insensitive. Plain byte values (like 65536) are accepted, but decimals (like 0.5MB) are not. The valid range is 64KB to 1MB. Values outside this range are rounded to the nearest limit. Defaults to 64KB.

Deprecation Notice

The Buffer size limit (bytes) setting replaces the deprecated Max buffer size setting to provide more predictable memory management in version 4.18.0. The Max buffer size setting will be removed in version 4.19.1. For upgraded Worker Groups and Fleets, the new byte-based limit defaults to 64KB. Update your configurations to the new byte-based limit to ensure optimal memory stability.

Strict ordering: Toggle on (default) to enable FIFO (first in, first out) event forwarding, ensuring Cribl Stream/Edge sends earlier queued events first when receivers recover. The persistent queue flushes every 10 seconds in this mode. Toggle off to prioritize new events over queued events, configure a custom drain rate for the queue, and display this option:

• Drain rate limit (EPS): Optionally, set a throttling rate (in events per second) on writing from the queue to receivers. (The default 0 value disables throttling.) Throttling the queue drain rate can boost the throughput of new and active connections by reserving more resources for them. You can further optimize Worker startup connections and CPU load in the Worker Processes settings.

Clear Persistent Queue: For Cloud Enterprise only, select this button if you want to delete the files that are currently queued for delivery to this Destination. If you select this button, a confirmation modal appears. Clearing the queue frees up disk space by permanently deleting the queued data, without delivering it to downstream receivers. This button only appears after you define the Output ID.

Use the Clear Persistent Queue button with caution to avoid data loss. See Steps to Safely Disable and Clear Persistent Queues for more information.

Processing Settings ​

Post-Processing ​

Pipeline: Pipeline or Pack 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 - both metric events, as dimensions; and log events, as labels. Supports wildcards.

By default, includes cribl_pipe (Cribl Stream Pipeline that processed the event).

Other options include:

• cribl_host - Cribl Stream Node that processed the event.
• cribl_input - Cribl Stream Source that processed the event.
• cribl_output - Cribl Stream Destination that processed the event.
• cribl_route - Cribl Stream Route (or QuickConnect) that processed the event.
• cribl_wp - Cribl Stream Worker Process that processed the event.

Retries ​

This tab is displayed when General Settings > Optional Settings > Protocol is set to HTTP.

Honor Retry-After header: Toggle on to honor a Retry-After header, provided that the header specifies a delay no longer than 180 seconds. Cribl Stream/Edge limits the delay to 180 seconds even if the Retry-After header specifies a longer delay. Any Retry-After header received takes precedence over all other options configured in the Retries section. Toggle off to ignore all Retry-After headers.

Default Retry Behavior: By default, Cribl Stream/Edge applies predefined retry strategies for certain failed requests to the Destination using an exponential backoff algorithm. You can override these settings by manually configuring the retry behavior for a particular error code.

Destinations created before the 4.16.0 release do not support the default 4xx series retry behavior. If your Destination was created prior to this release and you’d like it to support the behavior, reconfigure the Destination.

To retry requests, Cribl Stream/Edge applies the following rules by default:

By default, any 429 (Too Many Requests) response that is not listed in the retry settings is treated as a non-retryable 4xx error and dropped. If you want 429 responses retried, ensure 429 is included in the Settings for failed HTTP requests.

Settings for failed HTTP requests: You can also manually configure Cribl Stream/Edge to automatically retry requests that receive particular HTTP response status codes.

Upon receiving a response code that’s on the list, Cribl Stream/Edge first waits for a set time interval called the Pre-backoff interval and then begins retrying the request. Time between retries increases based on an exponential backoff algorithm whose base is the Backoff multiplier, until the backoff multiplier reaches the Backoff limit (ms). At that point, Cribl Stream/Edge continues retrying the request without increasing the time between retries any further.

If the sender (which manages the connection to the Destination) is at capacity, it will not accept any incoming events. These incoming events originate internally from a previous stage of the data flow when Destinations send outbound requests to their respective external services, and they include retry requests and new requests. Any events that were already in transit when the sender reached capacity will continue to be processed downstream.

Sender capacity is freed up when an outgoing request succeeds or encounters a non-retryable error. When the sender has available capacity again, it will resume accepting incoming events. This capacity management is influenced by the number of active connections and configured limits, such as concurrency and buffer sizes. If a Pipeline sends events faster than the Destination can process, the buffers may fill up, leading to backpressure and Sender at capacity warnings. This backpressure prevents the sender from accepting additional requests until capacity is restored.

For each response code you want to add to the list, select Add Setting and configure the following settings:

• HTTP status code: A response code that indicates a failed request, for example 429 (Too Many Requests) or 503 (Service Unavailable).
• Pre-backoff interval (ms): The amount of time to wait before beginning retries, in milliseconds. Defaults to 1000 (one second).
• Backoff multiplier: The base for the exponential backoff algorithm. A value of 2 (the default) means that Cribl Stream/Edge will retry after 2 seconds, then 4 seconds, then 8 seconds, and so on.
• Backoff limit (ms): The maximum backoff interval Cribl Stream/Edge should apply for its final retry, in milliseconds. Default (and minimum) is 10,000 (10 seconds); maximum is 180,000 (180 seconds, or 3 minutes).

Retry timed-out HTTP requests: Toggle on to automatically retry requests that have timed out and display the following settings for configuring retry behavior:

• Pre-backoff interval (ms): The amount of time to wait before beginning retries, in milliseconds. Defaults to 1000 (one second).
• Backoff multiplier: The base for the exponential backoff algorithm. A value of 2 (the default) means that Cribl Stream/Edge will retry after 2 seconds, then 4 seconds, then 8 seconds, and so on.
• Backoff limit (ms): The maximum backoff interval Cribl Stream/Edge should apply for its final retry, in milliseconds. Default (and minimum) is 10,000 (10 seconds); maximum is 180,000 (180 seconds, or 3 minutes).

Advanced Settings ​

This tab’s options depend on whether General Settings > Protocol is set to the gRPC or HTTP transport. The common settings directly are displayed for both transports.

Compression: Compression type to apply to messages sent to the OpenTelemetry endpoint. Gzip (the default) and None are available for both protocols; Deflate is available for gRPC only.

Request timeout: Amount of time (in seconds) to wait for a request to complete before aborting it. Defaults to 30 sec.

Request concurrency: Maximum number of concurrent requests before blocking. This is set per Worker Process. Defaults to 5.

Body size limit (KB): Maximum size of the request body before compression. Defaults to 4096 KB. The actual request body size might exceed the specified value because the Destination adds bytes when it writes to the downstream receiver. Cribl recommends that you experiment with the Body size limit value until downstream receivers reliably accept all events.

Flush period (sec): Maximum time between requests. Low values could cause the payload size to be smaller than the configured Max body size. Defaults to 1 sec.

Environment: Optionally, specify a single Git branch on which to enable this configuration. If this field is empty, the config will be enabled everywhere.

Additional Settings for gRPC ​

When General Settings > Protocol is set to gRPC, the Advanced Settings tab adds the following options.

Connection timeout: Amount of time (milliseconds) to wait for the connection to establish before retrying. Defaults to 10000 (10 sec.).

Keep alive time (seconds): How often the sender should ping the peer to keep the connection alive. Defaults to 30.

Metadata: Static metadata to send with every gRPC request. Select Add Metadata to add each item as a Key-Value pair. The Value field is a JavaScript expression that is evaluated when the Destination is initialized. If you pass credentials as metadata, Cribl recommends using C.Secret().

Use dynamic metadata: Toggle on to enable per-event dynamic metadata on outbound gRPC requests. When enabled, Cribl Stream reads metadata key-value pairs from the field specified in Dynamic metadata field on each event, injects them into the gRPC request metadata, and batches together events that share the same metadata values. This lets you drive routing and integration behaviors in downstream observability systems based on data carried in the events themselves, without creating separate routes and Destinations for each combination. Dynamic metadata entries override any static Metadata entries with matching keys. Default is off.

Dynamic metadata field: The event field that contains the metadata key-value pairs to inject into outbound gRPC request metadata. Visible only when Use dynamic metadata is enabled. Each key in the object becomes a metadata key, and values must be strings, numbers, booleans, or null. Keys that would override protected values such as content-type are ignored. Events that do not contain this field are grouped into a single shared default batch rather than being separated by metadata values. No dynamic metadata is injected for these events; only the static Metadata entries apply. Defaults to __headersOut.

Additional Settings for HTTP ​

When General Settings > Protocol is set to HTTP, the Advanced Settings tab adds the following options.

Validate server certs: Toggle on to reject certificates that are not authorized by a CA in the CA certificate path, nor by another trusted CA (for example, the system’s CA).

Round-robin DNS: Toggle on to enable round-robin DNS lookup across multiple IP addresses, IPv4 and IPv6. When a DNS server resolves a Fully Qualified Domain Name (FQDN) to multiple IP addresses, Cribl Stream will sequentially use each address in the order they are returned by the DNS server for subsequent connection attempts.

Keep alive: By default, Cribl Stream sends Keep-Alive headers to the remote server and preserves the connection from the client side up to a maximum of 120 seconds. Toggle this off if you want Cribl Stream to close the connection immediately after sending a request.

Extra HTTP headers: Click Add Header to define additional HTTP headers to pass to all events. Each row is a Name-Value pair. Values will be sent encrypted.

Safe headers: Add headers here to declare them as safe to log in plaintext. (Sensitive headers such as authorization will always be redacted, even if listed here.) Use a tab or hard return to separate header names.

Troubleshooting ​

The Destination’s configuration modal has helpful tabs for troubleshooting:

Live Data: Try capturing live data to see real-time events as they flow through the Destination. On the Live Data tab, click Start Capture to begin viewing real-time data.

Logs: Review and search the logs that provide detailed information about the delivery process, including any errors or warnings that may have occurred.

Test: Ensures that the Destination is correctly set up and reachable. Verify that sample events are sent correctly by clicking Run Test.

You can also view the Monitoring page that provides a comprehensive overview of data volume and rate, helping you identify delivery issues. Analyze the graphs showing events and bytes in/out over time.