galera.galera_forced_binlog_format fails: Failed to start mysqld.2

galera.galera_forced_binlog_format fails with Failed to start mysqld.2 on the 11.4, 11.8 and 12.3 branches.

Build Run Info

Failure text

Latest run on 11.4 (worker number, timestamps and paths differ between runs; the other release branch runs show the same message):

galera.galera_forced_binlog_format       w12 [ fail ]

        Test ended at 2026-10-09 13:33:02

CURRENT_TEST: galera.galera_forced_binlog_format

Failed to start mysqld.2

mysqltest failed but provided no output

 - saving '/home/buildbot/ppc64le-ubuntu-2204/build/mysql-test/var/12/log/galera.galera_forced_binlog_format/' to '/home/buildbot/ppc64le-ubuntu-2204/build/mysql-test/var/log/galera.galera_forced_binlog_format/'

Retrying test galera.galera_forced_binlog_format, attempt(2/3)...

Analysis

Two builders are affected: ppc64le-ubuntu-2204 (11.4, 11.8, 12.3) and aarch64-debian-12 (11.4, 12.3). In the 7 days to 2026-10-12 the failure was recorded 46 times, all on these two builders: 7 rows on release branches and 39 on PR and bb-* branches. The buildbot text is the same in all 46 rows. Each of the 7 release branch runs also failed galera.galera_partitioned_tables (MDEV-40688) and galera.MDEV-27862 (MDEV-40355) with the same message. MDEV-40688 traces the message on galera.galera_partitioned_tables to the joining node's wsrep_sst_rsync exiting with 2 (No such file or directory); PR 5603 for that ticket skips galera tests when wsrep SST prerequisites are missing and is not merged. MDEV-40355 describes several unrelated tests failing at the same instant under --parallel=14 when the SST joiners fail to establish quorum together.

Created via the mtr-failure-bug skill.