Since the upgrade to mariadb 10.11.15, the mariadb service fails to start:

Jan 11 09:00:57 systemd[1]: Starting mariadb.service - MariaDB 10.11 database server...
Jan 11 09:00:57 mariadb-prepare-db-dir[1389]: Database MariaDB is probably initialized in /var/lib/mysql already, nothing is done.
Jan 11 09:00:58 mariadb-prepare-db-dir[1389]: If this is not the case, make sure the /var/lib/mysql is empty before running mariadb-prepare-db-dir.
Jan 11 09:00:58 (mariadbd)[1513]: mariadb.service: Referenced but unset environment variable evaluates to an empty string: MYSQLD_OPTS, _WSREP_NEW_CLUSTER
Jan 11 09:00:59 systemd-coredump[1622]: Process 1513 (mariadbd) of user 27 dumped core.

Looking into the mariadb log file reveals that it fails to create the PID file:

2026-01-12  7:55:48 0 [Note] Server socket created on IP: '0.0.0.0', port: '3306'.
2026-01-12  7:55:48 0 [Note] Server socket created on IP: '::', port: '3306'.
2026-01-12  7:55:48 0 [ERROR] mariadbd: Can't create/write to file '/run/mariadb/mariadb.pid' (Errcode: 2 "No such file or directory")
2026-01-12  7:55:48 0 [ERROR] Can't start server: can't create PID file: No such file or directory
terminate called without an active exception
260112  7:55:48 [ERROR] /usr/libexec/mariadbd got signal 6 ;
Sorry, we probably made a mistake, and this is a bug.

Your assistance in bug reporting will enable us to fix this for the next release.
To report this bug, see https://mariadb.com/kb/en/reporting-bugs about how to report
a bug on https://jira.mariadb.org/.

Please include the information from the server start above, to the end of the
information below.

Server version: 10.11.15-MariaDB source revision: cb0d6dd835023a7162ace471cd047161f205dd58

The information page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mariadbd/
contains instructions to obtain a better version of the backtrace below.
Following these instructions will help MariaDB developers provide a fix quicker.

Attempting backtrace. Include this in the bug report.
(note: Retrieving this information may fail)

Thread pointer: 0x0
stack_bottom = 0x0 thread_stack 0x49000
/usr/libexec/mariadbd(my_print_stacktrace+0x3d) [0x55b37bc9e20d]
/usr/libexec/mariadbd(handle_fatal_signal+0x299) [0x55b37b812009]
/lib64/libc.so.6(+0x1a040) [0x7f394ea29040]
/lib64/libc.so.6(+0x73e5c) [0x7f394ea82e5c]
/lib64/libc.so.6(gsignal+0x1e) [0x7f394ea28f0e]
/lib64/libc.so.6(abort+0x26) [0x7f394ea106d0]
/lib64/libstdc++.so.6(+0x91b4) [0x7f394ec091b4]
/lib64/libstdc++.so.6(+0x1eb9c) [0x7f394ec1eb9c]
/lib64/libstdc++.so.6(_ZSt10unexpectedv+0x0) [0x7f394ec08d3a]
/usr/libexec/mariadbd(+0x7d61b) [0x55b37b39b61b]
/lib64/libc.so.6(+0x1c7e1) [0x7f394ea2b7e1]
/lib64/libc.so.6(+0x1c8be) [0x7f394ea2b8be]
/usr/libexec/mariadbd(signal_hand+0x562) [0x55b37b40d222]
/usr/libexec/mariadbd(+0x6ffa51) [0x55b37ba1da51]
/lib64/libc.so.6(+0x71f14) [0x7f394ea80f14]
/lib64/libc.so.6(+0xf52ec) [0x7f394eb042ec]
Writing a core file...
Working directory at /var/lib/mysql
Resource Limits (excludes unlimited resources):
Limit                     Soft Limit           Hard Limit           Units     
Max stack size            8388608              unlimited            bytes     
Max processes             126690               126690               processes 
Max open files            32188                32188                files     
Max locked memory         8388608              8388608              bytes     
Max pending signals       126690               126690               signals   
Max msgqueue size         819200               819200               bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Core pattern: |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %d %F

Kernel version: Linux version 6.18.4-100.fc42.x86_64 (mockbuild@8576370b411640ad9399cbbec5c01b67) (gcc (GCC) 15.2.1 20251211 (Red Hat 15.2.1-5), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_
DYNAMIC Thu Jan  8 18:43:17 UTC 2026

The issue is that /run/mariadb does not exist. Indeed, it is owned by the mariadb-server package, but /run is a tmpdir and thus may be purged at reboot.

Creating the directory fixes the issue.

I'm not sure why this only started occurring with version 10.11.15 and I'm not daring to downgrade mariadb on a production machine. Maybe the configured path for the pid-file has changed?

It seems that on Fedora 43, this is solved by including a tmpfiles config for mariadb. The config does not exist on Fedora 42.

Reproducible: Always

Steps to Reproduce:
1. Upgrade to mariadb-server 10.11.15
2. Reboot

Note: I don't know if this can be reproduced by just installing 10.11.15 or whether it's caused by a %config(noreplace) from an older version or something similar.
Actual Results:
mariadb-server fails to start because /run/mariadb does not exist.

Expected Results:
The service starts.