If it’s happening every 15 minutes, it’s probably a systemd timer trying to kick off a unit on a schedule. Check for .timer files in your system and user systemd configuration and see if there are any configured to run every 15 minutes.
Whatever process is trying to start is probably exceeding the open files ulimit. ulimits can be set system-wide, per user, and per cgroup.
The ulimit may be too low, there may be some process leaking file handles (opening files periodically but never closing them), or the unit might be configured to run under the wrong user or cgroup.
If a reboot gets rid of the problem temporarily, it’s most likely a file handle leak. Remember that objects like network sockets also count as files for the purposes of the open files ulimit.
A tool like lsof can help you track down processes with a lot of open file handles.
If it’s happening every 15 minutes, it’s probably a systemd timer trying to kick off a unit on a schedule. Check for .timer files in your system and user systemd configuration and see if there are any configured to run every 15 minutes.
Whatever process is trying to start is probably exceeding the open files ulimit. ulimits can be set system-wide, per user, and per cgroup.
The ulimit may be too low, there may be some process leaking file handles (opening files periodically but never closing them), or the unit might be configured to run under the wrong user or cgroup.
If a reboot gets rid of the problem temporarily, it’s most likely a file handle leak. Remember that objects like network sockets also count as files for the purposes of the open files ulimit.
A tool like lsof can help you track down processes with a lot of open file handles.