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OpenTelemetry (OTel)

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

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

Protocol and Transport Support
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In Cribl Edge 4.1 and later, 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 currently 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:

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

Configuring Cribl Edge to Output to OTel
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From the top nav, click Manage, then select a Fleet to configure. Next, you have two options:

To configure via the graphical QuickConnect UI, click Routing > QuickConnect (Stream) or Collect (Edge). Next, click Add Destination at right. From the resulting drawer’s tiles, select OpenTelemetry. Next, click either Add Destination or (if displayed) Select Existing. The resulting drawer will provide the options below.

Or, to configure via the Routing UI, click Data > Destinations (Stream) or More > Destinations (Edge). From the resulting page’s tiles or the Destinations left nav, select OpenTelemetry. Next, click Add Destination to open a New Destination modal that provides the options below.

General Settings
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Output ID: Enter a unique name to identify this OTel output definition.

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.

Optional Settings
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Protocol: Use the drop-down to choose the protocol to use when sending data: gRPC (the default), or HTTP. When set to HTTP, the UI displays two additional settings:

  • 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 traces 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.

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 in Cribl Edge’s Manage Destinations page. These tags aren’t added to processed events. Use a tab or hard return between (arbitrary) tag names.

TLS Settings (Client Side)
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TLS is available only when General Settings > Protocol is set to gRPC.

Enabled Defaults to No. When toggled to Yes:

Validate server certs: Reject certificates that are not authorized by a CA in the CA certificate path, nor by another trusted CA (e.g., the system’s CA). Defaults to Yes.

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 name: The name of the predefined certificate.

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.

Authentication
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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. E.g.: 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.

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

On Cribl-managed Cribl.Cloud Workers (with an Enterprise plan), this tab exposes only the destructive Clear Persistent Queue button (described below in 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 Edge will block outbound data. To configure the queue size, compression, queue-full fallback behavior, and other options below, use a hybrid Group.

Max file size: 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.

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.

Clear Persistent Queue: Click this “panic” button if you want to delete the files that are currently queued for delivery to this Destination. A confirmation modal will appear - because this will free up disk space by permanently deleting the queued data, without delivering it to downstream receivers. (Appears only after Output ID has been defined.)

Strict ordering: The default Yes position enables FIFO (first in, first out) event forwarding. When receivers recover, Cribl Edge will send earlier queued events before forwarding newly arrived events. To instead prioritize new events before draining the queue, toggle this off. Doing so will expose this additional control:

  • 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’s drain rate can boost the throughput of new/active connections, by reserving more resources for them. You can further optimize Workers’ startup connections and CPU load at Fleet Settings > Worker Processes.

Processing Settings
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Post‑Processing
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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 – both metric events, as dimensions; and log events, as labels. Supports wildcards.

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

Other options include:

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

Advanced Settings
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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.

Common Settings
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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.

Max body size (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 Max body size 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
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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: Extra information to send with each gRPC request. Click Add Metadata to add each item as a Key-Value pair. The Key field is arbitrary. The Value field is a JavaScript expression that is evaluated just once, when this Destination is initialized. If you pass credentials as metadata, Cribl recommends using C.Secret().

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

Validate server certs: Toggle to Yes to reject certificates that are not authorized by a CA in the CA certificate path, nor by another trusted CA (e.g., 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 Edge will sequentially use each address in the order they are returned by the DNS server for subsequent connection attempts.

Keep alive: By default, Cribl Edge 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 Edge 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.