Azure Data Explorer

Cribl Stream supports sending data to the Azure Data Explorer (ADX) managed data analytics service; you can then run Kusto queries against the data. This Destination can deliver data to Azure whether Cribl Stream is running on Azure, another cloud platform, or on-prem.

ADX stores log data in databases, which in turn contain one or more of the tables defined in the Azure namespace. You must create a separate Cribl Stream ADX Destination for each table that will store your data.

Type: Non-Streaming or Streaming (configurable) | TLS Support: Yes | PQ Support: No

Prerequisites​

Before you configure the Destination, you need to collect some information from your Azure deployment. Start from Home (portal.azure.com), then navigate to the locations described below and collect the items specified.

Information About Your ADX Cluster​

From Home, navigate to:

Azure Data Explorer Clusters > your_Azure_cluster_name > Overview > Essentials

  • Copy the URI. In Cribl Stream, this will be the value for General Settings > Cluster base URI. Make a copy of the URI with /.default appended – this will be the value of Authentication Settings > Scope.

  • Copy the Data Ingestion URI. In Cribl Stream, this will be the value for General Settings > Ingestion service URI.

Information About Your Azure Database​

From Home, navigate to:

Azure Data Explorer Clusters > your_Azure_cluster_name | Databases > database_name | Query

  • Note the name of your desired target table – this table name will be the value of General Settings > Table name.

Information About Your Azure App​

First, from Home, navigate to:

App registrations > your_Azure_app_name | Overview | Essentials

  • Copy the Application (client) ID – this will be the value of Authentication Settings > Client ID.

  • Copy the Directory (tenant) ID – this will be the value of Authentication Settings > Tenant ID.

Nex, from Home, navigate to:

App registrations > your_Azure_app_name | Certificates & secrets

Now what you do depends on which method for Authentication you plan to use in Cribl Stream.

To use the Client secret method​
  • In the Client secrets tab, click New client secret and copy the Value of the new secret. In Cribl Stream, this will be the value of Client secret.
To use the Client secret (text secret) method​
  • In the Client secrets tab, click New client secret and copy the Value of the new secret. In Cribl Stream, this will be the value of Create new secret > Value.
To use the Certificate method​

After you have generated a certificate and keys (if you do this later on in the configuration process, return to this section then):

  • In the Certificates tab, click Upload Certificate. In the resulting drawer, follow the prompts to upload your certificate, and click Add to close the drawer.

The chosen certificate will then appear in the Certificates tab’s list.

Data Mapping Prerequisites​

Finally, you might need to note or copy data mapping information to obtain values for some of the General Settings.

ADX uses a data mapping to map fields from incoming data to fields in the target table. To see the data mapping, you’ll run a Kusto query against your target table.

Here’s the query syntax:

.show table EntityName ingestion MappingKind mapping MappingName

Here’s an example query:

.show table SyslogTable ingestion json mapping "SyslogMapping"

The Kusto query that originally created this mapping would look like this:

.create table SyslogTable ingestion json mapping "SyslogMapping"

In Cribl Stream, you can use the names of mappings like the above example in the General Settings > Data mapping field. Alternatively, you can create a mapping without naming it, then copy and paste it (as a JSON object) into the Cribl Stream UI. To do this, toggle General Settings > Mapping object on. This hides the default Data mapping text field and opens a text window that expects JSON.

Configuring Cribl Stream to Output to Azure Data Explorer​

From the top nav, click Manage, then select a Worker Group 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 Azure > Azure Data Explorer. 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 Azure > Azure Data Explorer. Next, click Add Destination to open a New Destination modal that provides the options below.

General Settings​

This Destination supports two ingestion modes:

  • Batching (the default) stages data in a storage container from which ADX pulls batches of data, then writes them to the target ADX table. Batching works well when the Destination needs to ingest large amounts of data in short periods of time.
  • Streaming sends data as HTTP request payloads, directly to the target ADX table, without staging them in a container first. Streaming can achieve lower latency than batching, as long as the data that the Destination ingests arrives in relatively small amounts.

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

Ingestion mode: Use the buttons to select Batching mode (the default) or Streaming mode.

Cluster base URI: Enter the base URI for your ADX cluster.

Ingestion service URI: Displayed only in Batching mode. Enter the Ingestion Service URI for your ADX cluster.

Database name: Enter the name of the ADX database where the target table resides.

Table name: Enter the name of the target table.

Validate database settings: When you save or start the Destination, validates the database name and credentials that you have entered in these settings. Also validates the table name, except when Add mapping object (below) is on. Defaults to Yes. Disable if your Azure app does not have both the Database Viewer and the Table Viewer role.

Add mapping object: Displayed only in Batching mode, this control is toggled off by default. Toggle on when you want to paste in a data mapping as a JSON object, instead of using a named data mapping. See Data Mapping Prerequisites above.

Data mapping: If Add mapping object is off, enter the name of the desired data mapping. If Add mapping object is on, enter the desired data mapping as a JSON object.

Compress: By default, this Destination compresses data using gzip; otherwise it sends the data uncompressed. This setting is not available when Data format is set to Parquet.

Data format: The output data format defaults to JSON. Raw and Parquet are also available. Selecting Parquet (available only in Batching mode, and supported only on Linux, not Windows) exposes a Parquet Settings tab, where you select the Parquet schema.

Backpressure behavior: Whether to block or drop events when all receivers are exerting backpressure. (Causes might include an accumulation of too many files needing to be closed.) Defaults to Block. When Ingestion mode is set to Streaming mode, the Persistent Queue option becomes available. See Persistent Queue Settings below.

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

Authentication Settings ​

Microsoft Entra ID authentication endpoint: From the drop-down, select the Microsoft Entra ID endpoint that provides authentication tokens. To understand the available choices, see the Microsoft Entra documentation.

Tenant ID: Directory ID (tenant identifier) in Microsoft Entra ID.

Client ID: client_id to pass in the OAuth request parameter.

Scope: Scope to pass in the OAuth request parameter.

Use the Authentication method buttons to select one of these options:

  • Client secret: Use this default option to enter the client secret that you generated for your app in the Azure portal.

  • Client secret (text secret): Use this option to select (or create) a stored text secret.

  • Certificate: Use this option to select the certificate whose public key you register (or will register) for your app in the Azure portal. Or, create a new one.

Persistent Queue Settings​

This tab is displayed when General Settings > Ingestion mode is set to Streaming mode and Backpressure behavior is set to Persistent Queue.

On Cribl-managed Cribl.Cloud Worker Nodes (with an Enterprise plan), this tab should expose only the destructive Clear Persistent Queue button (described below in this section).

Due to Known Issue CRIBL-21335, the on-prem Persistent Queue settings are still displayed in Cribl.Cloud – but you should ignore all controls other than the Clear Persistent Queue button.

The other controls are not needed because Cribl.Cloud automatically allocates a maximum queue size of 1 GB disk space 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 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 that the queue is allowed to consume on each Worker Process. Once this limit is reached, this Destination will stop queueing data and apply the Queue‑full behavior. Required, and defaults to 5 GB. Accepts positive numbers with units of KB, MB, GB, etc. Can be set as high as 1 TB, unless you’ve configured a different Max PQ size per Worker Process in Group Settings.

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.

Strict ordering: The default Yes position enables FIFO (first in, first out) event forwarding. When receivers recover, Cribl Stream 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 Group Settings > Worker Processes.

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.)

Processing Settings​

Post‑Processing​

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 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.

Parquet Settings​

To write out Parquet files, note that:

  • On Linux, you can use the Cribl Stream CLI’s parquet command to view a Parquet file, its metadata, or its schema.
  • Cribl Edge Workers support Parquet only when running on Linux, not on Windows.
  • See Working with Parquet for pointers on how to avoid problems such as data mismatches.

Automatic schema: Toggle on to automatically generate a Parquet schema based on the events of each Parquet file that Cribl Stream writes. When toggled off (the default), exposes the following additional field:

  • Parquet schema: Select a schema from the drop-down.

If you need to modify a schema or add a new one, follow the instructions in our Parquet Schemas topic. These steps will propagate the freshest schema back to this drop-down.

Parquet version: Determines which data types are supported and how they are represented. Defaults to 2.6; 2.4 and 1.0 are also available.

Data page version: Serialization format for data pages. Defaults to V2. If your toolchain includes a Parquet reader that does not support V2, use V1.

Group row limit: The number of rows that every group will contain. The final group can contain a smaller number of rows. Defaults to 10000.

Page size: The target memory size for page segments. Generally, lower values improve reading speed, while higher values improve compression. Must be a positive integer smaller than the Row group size value, with appropriate units. Defaults to 1 MB.

Log invalid rows: Toggle to Yes to output up to 20 unique rows that were skipped due to data format mismatch. Log level must be set to debug for output to be visible.

Write statistics: Leave toggled on (the default) if you have Parquet tools configured to view statistics – these profile an entire file in terms of minimum/maximum values within data, numbers of nulls, etc.

Write page indexes: Leave toggled on (the default) if your Parquet reader uses statistics from Page Indexes to enable page skipping. One Page Index contains statistics for one data page.

Write page checksum: Toggle on if you have configured Parquet tools to verify data integrity using the checksums of Parquet pages.

Metadata (optional): The metadata of files the Destination writes will include the properties you add here as key-value pairs. For example, one way to tag events as belonging to the OCSF category for security findings would be to set Key to OCSF Event Class and Value to 2001.

Retries​

This tab is displayed when General Settings > Ingestion mode is set to Streaming mode.

HTTP Retry Settings: When you want to automatically retry requests that receive particular HTTP response status codes, use these settings to list those response codes.

Upon receiving a response code that’s on the list, Cribl Stream first waits for a set time interval called the HTTP 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. Retries continue until the backoff multiplier reaches the Backoff limit (ms), or until the request succeeds, whichever comes first.

By default, 429 (Too Many Requests) is the only response code configured for automatic retries. For each response code you want to add to the list, click 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 will retry after 2 seconds, then 4 seconds, then 8 seconds, and so on.
  • Backoff limit (ms): The maximum backoff interval Cribl Stream 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).

Timeout: When you want to automatically retry requests that have timed out, toggle Timeout on. This option displays 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 will retry after 2 seconds, then 4 seconds, then 8 seconds, and so on.
  • Backoff limit (ms): The maximum backoff interval Cribl Stream 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​

The controls on this tab vary depending on the Ingestion mode selected on the General Settings tab. Below you’ll find one dedicated section for the Batching, and another for the Streaming controls.

Only the Environment control, at the bottom of the tab, is common to both:

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.

Advanced Settings for Batching Mode​

Flush immediately: Toggle on to bypass the data management service’s aggregation mechanism. See the ADX documentation.

Retain blob on success: By default, Cribl Stream deletes each data blob once ingestion is complete. Toggle this on if you prefer to retain blobs instead.

Extent tags: Optionally, add strings or tags to partitions of the target table – Azure calls these extents or data shards.

Enforce uniqueness via tag values: Use the Add value button to specify a list of ingest-by values. Cribl Stream will then check the ingest-by tags of incoming extents and discard those whose values match a listed value. This mechanism for avoiding ingesting duplicate extents uses the ingestIfNotExists property, as described in the ADX documentation.

Report level: Level for ingestion status reporting. Options are DoNotReport, FailuresOnly (the default), and FailuresAndSuccesses.

Report method: Target for ingestion status reporting. Options are Queue (the default), Table, and QueueAndTable.

Additional fields: Optionally, enter additional configuration properties to send to the ingestion service.

Staging location: Local filesystem location in which to buffer files before compressing and moving them to the final destination. Cribl recommends that this location be stable and high-performance. Defaults to /tmp.

File name suffix expression: The output filename suffix. Must be a JavaScript expression (which can evaluate to a constant), enclosed in quotes or backticks.

Defaults to `.${C.env["CRIBL_WORKER_ID"]}.${__format}${__compression === "gzip" ? ".gz" : ""}`, where __format can be json or raw, and __compression can be none or gzip.

To prevent files from being overwritten, Cribl appends a random sequence of 6 characters to the end of their names. File name prefix and suffix expressions do not bypass this behavior.

For example, if you set the File name prefix expression to CriblExec and set the File name suffix expression to .csv, the file name might display as CriblExec-adPRWM.csv with adPRWM appended.

Max file size (MB): Maximum uncompressed output file size. Files reaching this size will be closed and moved to the storage container. Defaults to 32.

Max file open time (sec): Maximum amount of time to write to a file. Files open for longer than this limit will be closed and moved to the storage container. Defaults to 300 seconds (5 minutes).

Max file idle time (sec): Maximum amount of time to keep inactive files open. Files open for longer than this limit will be closed and moved to the storage container. Default: 30.

Max open files: Maximum number of files to keep open concurrently. When exceeded, the oldest open files will be closed and moved to the storage container. Default: 100.

Max concurrent file parts: Maximum number of parts to upload in parallel per file. A value of 1 tells the Destination to send one part at a time – that is, to upload the file’s contents sequentially. Defaults to 1; highest allowed value is 10.

Add output ID: Toggle on if you want Cribl Stream to append the Destination name to staging directory pathnames. This can make it easier to organize and troubleshoot when you have multiple Destinations populating staging directories.

Remove empty staging dirs: When toggled on (the default), Cribl Stream deletes empty staging directories after moving files. This prevents the proliferation of orphaned empty directories. When enabled, exposes this additional option:

  • Staging cleanup period: How often (in seconds) to delete empty directories when Remove staging dirs is enabled. Defaults to 300 seconds (every 5 minutes). Minimum configurable interval is 10 seconds; maximum is 86400 seconds (every 24 hours).

Advanced Settings for Streaming Mode​

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 per Worker Process. When Cribl Stream hits this limit, it begins throttling traffic to the downstream service. Defaults to 5. Minimum: 1. Maximum: 32.

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 settings could cause the payload size to be smaller than its configured maximum. Defaults to 1.

Validate server certs: When toggled on (the default) Cribl Stream will reject certificates that are not authorized by a CA in the CA certificate path, nor by another trusted CA (such as the system’s CA, for example).

Round-robin DNS: Toggle to Yes to use round-robin DNS lookup across multiple IPv6 addresses. When a DNS server returns multiple addresses, this will cause Cribl Stream to cycle through them in the order returned.

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.

Internal Fields​

Cribl Stream uses a set of internal fields to assist in forwarding data to a Destination.

Field for this Destination:

  • __partition

Proxying Requests​

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