Unit maintains a single general-purpose log for diagnostics and troubleshooting (not to be confused with the access log). To find out its default location in your Unit installation:

$ unitd --help

    unit options:
    --log FILE           set log filename
                         default: "/path/to/unit.log"

The --log option overrides the default value; if Unit is already running, check whether this option is set:

$ ps ax | grep unitd
    unit: main v1.17.0 [/path/to/unitd ... --log /path/to/unit.log ...]

If Unit isn’t running, see its system startup scripts or configuration files to check if --log is set, and how.


Mind that our Docker images forward their log output to the Docker log collector instead of a file.

Debug Log§

Unit log has two verbosity modes: common and debug; steps to enable the latter vary by install method.


Debug log is meant for developers; it grows rapidly, so enable it only for detailed reports and inspection.

Installing From Our Repos§

Our repositories provide a debug version of unitd called unitd-debug within the unit package:

# unitd-debug <command line options>


Also, there are debug symbol packages for core dump analysis; their names end in -dbg, like unit-dbg.

Running From Docker Images§

To enable debug-level logging when using our Docker images:

$ docker run -d nginx/unit:1.17.0-full unitd-debug --no-daemon \
             --control unix:/var/run/control.unit.sock

Another option is adding a new layer in a Dockerfile:

FROM nginx/unit:1.17.0-full

CMD ["unitd-debug","--no-daemon","--control","unix:/var/run/control.unit.sock"]

The CMD instruction above replaces the default unitd executable with its debug version.

Building From Source§

To enable debug-level logging when installing from source, use the --debug option:

$ ./configure --debug <other options>

Then recompile and reinstall Unit and your specific language modules.

Getting Support§

Post your questions to our mailing list at; to subscribe, email or sign up here. You can also visit our GitHub repo to report an issue, suggest a feature, or share a problem.

In addition, we offer commercial support.