Frequently asked questions (FAQ)

General

When running any Docker Compose bundle, I get permission errors in various places. What am I doing wrong?

You probably missed certain instructions of the installation steps. Carefully re-read the installation guide and check each and every step. There are certain initialization steps, which create the required directories or set according permissions. It is also possible that you are starting services with the wrong user. For example you are running Docker as root or you are having wrong ownership of the files and directories in the /opt/aura directory.

After changing some setting in the configuration file, why does it have no effect?

Double-check if the configuration line is commented out. Remove the # at the beginning of the line, to enable the setting. Any commented out settings, do not necessarily indicate the default setting. Also, check the descriptions provided with the settings and compare with instructions in the documentation.

When logging out from the server via SSH, the Docker Containers stop running. Why is that?

It looks like your Docker Engine installation is bound to your session. Install Docker running as a daemon. We also recommend running Docker Engine in the rootless using systemd.

Why is there a blank page or `404`, when browsing to the Dashboard or after clicking login on my fresh installation?

This can have multiple reasons:

If you are have installed AURA locally remember not to use localhost or 127.0.0.1. This is the most common pitfall.
You have not initialized the OIDC clients correctly.
Your containers are not up- and running, or they are not healthy. Check the running containers and logs.

For all of these scenarios, check the installation steps for details.

Playout (Pipewire)

Why is my audio and any timeslot transitions delayed for 15-20 seconds during playout?

Most likely you have PulseAudio installed or running your playout through the Pipewire PulseAudio plugin. Get rid of PulseAudio completely and retry.

Playout (ALSA)

I am using the `default` audio device. How can I set another default device?

You can check the systems default audio hardware by executing aplay -L on the command line.

You can set the default device in /etc/asound.conf or ~/asoundrc.

How can I retrieve available ALSA audio devices?

To see only the physically available sound cards: cat /proc/asound/cards
To see sound cards with all additional devices (e.g. HDMI): aplay -l
To see devices configured by ALSA with additional plugins: aplay -L
The default devices that should be used: aplay -L | grep default

I have configured an audio device, but why do I still hear no sound (bare metal installation)?

To test if you device is able to output audio at all, independently from Engine Core, try executing speaker-test. Also checkout out the -D argument to test specific devices. If you system doesn’t provide speaker-test you have to install or use your preferred way of testing also audio.

I have configured an audio device but still hear no sound (Docker installation)

If you are running Engine Core using Docker, run the aforementioned speaker-test from within your docker container by perform following:

Bash into the container using docker exec -it aura-engine-core bash
Now run speaker-test. It that’s working, you now know that your audio device is at least available from within Docker and you’ll need to further check your Liquidsoap device configuration.
Next you can run liquidsoap tests/test_alsa_default.liq. This is a basic script which tries to play the supplied MP3 using the default ALSA device.

Why I am getting an `clock.wallclock_alsa:2 ...` error?

The error message also displays Error when starting output lineout: Failure("Error while setting open_pcm: No such file or directory").

Assure you have set the correct ALSA device ID. Review the audio interface configuration settings and verify if the default settings in the configuration file for your input and output devices are valid device IDs.

Also verify if the executing user (e.g. aura) belongs to the group audio.

How to solve `Error when starting output output_lineout_0: ...`?

The error message continues as Failure("Error while setting open_pcm: Device or resource busy")!.

You probably have set a wrong or occupied device ID. The device could be already reserved by another software using the ALSA sound system. Or you might be accessing a device using ALSA which is already assigned to the PulseAudio sound system. Here it could help to remove the device from PulseAudio before accessing it.

How to avoid stutter, hangs, artifacts or in general glitchy sound?

This can have various reasons, but first of all it’s good to check the engine-core.log file. Also check your CPU usage. Lastly review the settings of your audio device.

Incorrect ALSA buffer settings: If the ALSA settings provided by your system are not working cleanly the Engine Core settings provide to option to override parameters such as alsa_buffer. The correct settings are individual to the used soundcard but in general this is a tricky topic and deeper ALSA knowledge is very helpful.

These problems occur while having Icecast streaming enabled: Try to reduce the quality of the stream, especially when you are experiencing hangs on the stream. Check your Icecast connection. Is it up and running? Maybe there is some authentication issue or an Icecast limitation for max clients.

The hardware is hitting its limits: Also check the relevant logs and the system utilization. Are there other processes using up the machines resources? You might even be hitting the performance limit of your hardware. Maybe using a realtime linux kernel could help too.