Date: 11-04-2022

Linux Core Dumps

Sometimes OpenLDAP crashes and baffles the experts. When there is a crash or a slapd behavior we can't diagnose from logs, the data, or your configuration then a deeper look is needed. In those situations, troubleshooting requires the analysis of a core dump.

Default operating system settings often interfere with core dump creation. See Configuring Core Dumps  to ensure your system is properly configured to save and retain full core dump files.

Create a Core Dump by Killing slapd

If the process is still running and you need to kill it, send the slapd process a SIGQUIT signal:

Core Dump With kill

Get the slapd process ID

ps -C slapd

will show:

PID   TTY  TIME      CMD
23348 ?    15:35:33  slapd

Kill the process with a SIGQUIT signal:

kill -3 23348

OR

kill $(pgrep slapd)

After you kill the process, there should be a file with the name "core" in it in your current working directory or dedicated core file location.

Create a Core Dump Without Killing slapd

If you need a core dump but don't want or need to kill slapd, you can obtain the core dump by using the gcore utility.  This will create a core without disturbing the slapd process.

The gcore utility is not installed by default on some systems. You may need to install it to use this approach. gcore is a standard package on RHEL, OpenSuSE, Debian, and Ubuntu (and their derivative distributions).

To obtain a core with gcore, get the process id of slapd:

ps -C slapd

will display:

PID   TTY      TIME      CMD
23348 ?        15:35:33  slapd

then call gcore:

gcore 23348

OR

gcore $(pgrep slad)

The resulting core file should be in your current working directory and should have the id of the process that was dumped in the filename.