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Grafana Cloud
Last reviewed: October 22, 2026

Configure private probes

Customize how a Synthetic Monitoring private probe runs your checks by configuring optional features, private-IP access, and browser support. You can also control the agent’s usage reporting. For installation instructions, refer to Set up a private probe.

Configure feature flags

You can use feature flags to enable optional features in the private probe. Use a comma-separated list of feature names.

You can configure feature flags in either of the following ways:

  • On Linux package installations, edit /etc/synthetic-monitoring/synthetic-monitoring-agent.conf:

    ini 
    FEATURES="<comma-separated-feature-names>"

    Restart the agent service after changing the file.

  • Export the list of features as an environment variable:

    Bash 
    export FEATURES="<comma-separated-feature-names>"

    When starting the agent directly, pass the variable with --features="$FEATURES".

Available feature flags

Feature flag nameDescription

Current agents don’t require the adhoc, k6, or traceroute feature flags. If your configuration includes these names, remove them from FEATURES in your service configuration or from the --features command-line option.

Manual tests and traceroute checks are enabled without feature flags. Support for k6-based checks is enabled by default. To disable k6-based checks, start the agent with --disable-k6.

Depending on your environment, traceroute checks can require additional permissions for the probe process or container. Browser checks also have setup requirements beyond enabling k6 support.

Run k6 checks targeting private IP addresses

By default, private probes block k6 request targets in the 10.0.0.0/8 CIDR range. You can override this behavior by setting the CLI flag --blocked-nets="".

  • When running Docker, append --blocked-nets="" to your docker run command.
  • On Linux installations, run systemctl edit synthetic-monitoring-agent and append --blocked-nets="" to ExecStart=.

Run k6 browser checks on a private probe

To run k6 browser checks on private probes, you need a Chromium-compatible web browser on the system where the probe runs. In the probe settings page in your Grafana stack (Testing & synthetics > Synthetics > Probes), make sure that both Disable scripted checks and Disable browser checks are unchecked.

Linux package installations

Package installations of the Synthetic Monitoring Agent on Ubuntu, Debian, and RPM-based distributions require Chromium and a chromium binary available in $PATH. To use a specific Chromium installation without adding it to $PATH, set K6_BROWSER_EXECUTABLE_PATH in the agent’s environment to the binary’s full path. You can also set K6_BROWSER_ARGS with additional arguments that the agent uses when launching Chromium.

Container deployments

For Docker, Kubernetes, and other container-based environments, we provide a special image that already includes an installation of Chromium. These images are tagged with the -browser suffix, for example grafana/synthetic-monitoring-agent:vX.Y.Z-browser, as opposed to grafana/synthetic-monitoring-agent:vX.Y.Z.

Agent images tagged with the -browser suffix can run all types of checks, while those tagged without the -browser suffix can run every check type except k6 browser checks. If you do not plan to use browser checks, we recommend using the standard image, as it is lighter and more minimal. Swapping to a -browser image can be done at any time without any manual intervention, other than changing the tag.

Anonymous usage statistics reporting

Note

The anonymous usage statistics is enabled by default. You can opt out by setting the CLI flag -disable-usage-reports=true.

The statistics server

When usage statistics reporting is enabled, information is collected by a server that Grafana Labs operates. Statistics are sent to https://stats.grafana.org.

Which information is collected

When the usage statistics reporting is enabled, probes collect the following information:

  • Information about the probe, including:
    • A unique hash representation of the probe
    • The probe version, such as 0.39.0
    • The installation source, such as docker
    • The probe id, such as 1100
    • The tenant id, such as 1100
    • The features enabled, such as k6
  • Information about the environment, including:
    • The operating system, such as linux
    • The architecture, such as amd64
    • The os details, such as Ubuntu 24.04.2 LTS