These docs are for Cribl Stream 4.8 and are no longer actively maintained.
See the latest version (4.20).
Running Cribl Stream as a Non-Root User
We strongly recommended to never run Cribl Stream as the root user. Privileged access might be necessary, however, if Cribl Stream needs to read certain resources (such as /var/log/*), or to listen on low ports 0-1023. Here are two methods to grant this access while maintaining a non-root user:
Using Systemd capabilities: Set Linux capabilities that grant Cribl Stream sufficient rights to perform specific privileged tasks. For details, see Set Capabilities for Cribl Stream below.
Using setcap (Linux with POSIX capabilities): This method directly modifies the executable file to grant it specific privileges. For details, see Persisting Overrides on initd.
Set Capabilities for Cribl Stream
Capabilities are permissions that grant privileged processes sufficient rights to accomplish a specific task, based on a kernel privilege. To run Cribl Stream as non-root user, consider setting the following capabilities:
| Capability | Permissions |
|---|---|
CAP_NET_BIND_SERVICE | Allows Cribl Stream to push Sources that bind to TCP/UDP port numbers below 1024. |
CAP_DAC_READ_SEARCH | Allows the cribl user to access the File Monitor Source’s Manual mode feature. This capability bypasses the default Linux permissions for files and directories. |
CAP_SYS_PTRACE | Allows the cribl user to access the File Monitor Source’s Auto-mode feature. |
For details about setting these capabilities, see Persisting Overrides.
OS-Specific Options
On some OS versions (such as CentOS), you must add an -i switch to the setcap command. For example:
# setcap -i cap_net_bind_service=+ep $CRIBL_HOME/bin/cribl
Upgrading Cribl Stream will remove the CAP_NET_BIND_SERVICE capability from the cribl executable, so you’ll need to re-run the appropriate setcap command after each upgrade.
Changing Ownership of Cribl Stream After Startup
To change the ownership of Cribl Stream from root to a non-root user after the application has already been started, you must modify the ownership of both the primary installation directory ($CRIBL_HOME) and any Cribl Stream-related directories in the /tmp directory. If you changed the default /tmp directory location using the System > General Settings > Sockets > Directory setting, then adjust the location accordingly. Use the chown command to change the owner of these directories to the desired non-root user. To complete the process, restart the Cribl Stream application instance to ensure the changes take effect.