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Cribl HTTP

The Cribl HTTP Destination is available only in distributed deployments. It enables Edge Nodes to send data to peer Nodes, as long as all Nodes are connected to the same Leader.

You’ll find the Cribl HTTP Destination/Source pair especially valuable in a hybrid Cloud deployment, where it ensures that you’re billed for ingress only once – when Cribl first receives the data. All data subsequently transferred to other Workers via the Cribl HTTP Destination/Source pair is not charged. However, the Cribl HTTP Destination/Source pair can similarly reduce your metered data ingress in other scenarios, such as on-prem Edge to on-prem Stream.

In single‑instance mode, or for testing, you can substitute the Webhook Destination. (However, this substitution will not facilitate sending all internal fields, as described below.)

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

You might choose this Destination over the Cribl TCP Destination in certain circumstances, such as when a firewall or proxy blocks raw TCP egress.

Configuration Requirements
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Configuring Cribl HTTP flow between peer Edge Nodes imposes some particular requirements:

  • The Cribl HTTP Destination must be on a Edge Node that is connected to the same Leader as the Cribl HTTP Source(s).

  • You must specify the same Leader Address on the Edge Nodes that host both the Destination and Source. Otherwise, token verification will fail – breaking the connection and preventing data flow.

  • To get the Leader Address specifically for Cribl.Cloud hybrid Workers, see Hybrid Cribl HTTP/​Cribl TCP Configuration.

  • To configure the Leader Address via the UI, log directly into each Edge Node’s UI. Then select Settings > Global Settings > Distributed Settings > Leader Settings > Address.

  • To configure the Leader Address via the instance.yml file, the host values on the connecting Edge Nodes must be identical. In this example, both Edge Nodes must point to cribl-leader:

    distributed:
  mode: master
  master:
    host: cribl-leader
    port: 4200

  • This Destination’s Cribl endpoint field must point to the Address and Port you’ve configured on its peer Cribl HTTP Source(s).

  • Cribl 3.5.4 was a breakpoint in Cribl HTTP Leader/Worker communications. Edge Nodes running the Cribl HTTP Destination on Cribl Edge 3.5.4 and later can receive data only from Edge Nodes running v.3.5.4 and later. Edge Nodes running the Cribl HTTP Destination on Cribl Edge 3.5.3 and earlier can receive data only from Edge Nodes running v.3.5.3 and earlier.

Configuring a Cribl HTTP Destination
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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 Cribl HTTP. 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 Cribl HTTP. 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 Destination definition.

Load balancing: Set to No by default. When toggled to Yes, see Load Balancing Settings below.

Cribl endpoint: URL of a Cribl Worker to send events to, e.g., http://localhost:10200.

The Cribl endpoint field appears only when Load balancing is toggled to Off. Its value must point to the Address and Port you’ve configured on the peer Cribl HTTP Source to which you’re sending.

Optional Settings
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Compression: Codec to use to compress the data before sending. Defaults to Gzip.

Backpressure behavior: Specifies whether to block, drop, or queue events when all receivers are exerting backpressure. Defaults to Block. See Persistent Queue Settings below.

Tags: Optionally, add tags that you can use for filtering and grouping at the final destination. Use a tab or hard return between (arbitrary) tag names.

Load Balancing Settings
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Enabling the Load balancing slider displays the following controls.

Exclude Current Host IPs: This slider determines whether to exclude all IPs of the current host from the list of any resolved hostnames. Defaults to No. With the default No setting, if you notice that Cribl Edge is not sending data to all possible IP addresses, enable Advanced Settings > Round-robin DNS.

Cribl Worker Endpoints: In this table, you specify a set of Cribl Workers on which to load-balance data. To specify more Workers on new rows, click Add Endpoint. Each row provides the following fields.

  • Cribl Endpoint: Enter the URL of a Worker to send events to.

    Must point to the Address and Port configured on a peer Cribl HTTP Source to which you’re sending.

  • Load Weight: Specify a weight to apply to this Worker, for load-balancing purposes.

  • The final column provides an X button to delete any row from the table.

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

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, Cribl Stream stops queueing and applies the fallback Queue‑full behavior. Enter a numeral with units of KB, MB, etc.

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

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 button if you want to flush out files that are currently queued for delivery to this Destination. A confirmation modal will appear. (Appears only after Output ID has been defined.)

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. By default, includes cribl_pipe (identifying the Cribl Stream Pipeline that processed the event). Supports wildcards. 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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Validate server certs: Reject certificates that are not authorized by a CA in the CA certificate path, or by another trusted CA (e.g., the system’s CA). Defaults to Yes.

Round-robin DNS: Toggle to Yes to use round-robin DNS lookup across multiple IP addresses, IPv4 and IPv6. When a DNS server returns multiple addresses, this will cause Cribl Stream to cycle through them in the order returned. Only displayed when the General Settings tab’s Load balancing option is disabled.

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

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.

Max events per request: Maximum number of events to include in the request body. The 0 default allows unlimited events.

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

Extra HTTP headers: Name-value pairs to pass as additional HTTP headers.

Failed request logging mode: Use this drop-down to determine which data should be logged when a request fails. Select among None (the default), Payload, or Payload + Headers. With this last option, Cribl Stream will redact all headers, except non-sensitive headers that you declare below in Safe headers.

Safe headers: Add headers 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.

Exclude fields: Fields to exclude from the event. By default, __kube_* and __metadata are excluded. This Destination forwards all other Internal Fields.

If you are running Cribl Edge 4.0.x (or earlier) and are using the Kubernetes Metrics Source with this Destination, consider excluding the following fields to reduce event size:

!__inputId,!__outputId,!__criblMetrics,__* .

The contents of __raw are often redundant with the _raw field’s contents. Where they are identical, consider excluding one of the two.

Auth Token TTL minutes: The number of minutes before the internally generated authentication token expires, valid values between 1 and 60.

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.

The following options are added if you enable the General Settings tab’s Load balancing option:

DNS resolution period (seconds): Re-resolve any hostnames after each interval of this many seconds, and pick up destinations from A records. Defaults to 600 seconds.

Load balance stats period (seconds): Lookback traffic history period. Defaults to 300 seconds. (Note that If multiple receivers are behind a hostname – i.e., multiple A records – all resolved IPs will inherit the weight of the host, unless each IP is specified separately. In Cribl Stream load balancing, IP settings take priority over those from hostnames.)

Internal Fields Loopback to Sources
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The Cribl HTTP and Cribl TCP Destinations differ from all other Destinations in the way they handle internal fields: They normally send data back to their respective Cribl Sources – where Cribl internal fields, metrics, and sender-generated fields can all be useful.

These Destinations forward all internal fields by default, except for any that you exclude in Advanced Settings > Exclude fields.

As examples, if the following fields are present on an event forwarded by a Cribl HTTP or Cribl TCP Destination, they’ll be accessible in the ingesting Cribl HTTP/TCP Source:__criblMetrics, __srcIpPort, __inputId, and __outputId.

Proxying Requests
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If you need to proxy HTTP/S requests, see System Proxy Configuration.