The update in the OP help me resolve the same issue in this environment:

• RHEL 8.10

• Installed mysql-community-server-8.4.5-1.el8.x86_64 from mysql-8.4-lts-community repo.

• LDAP already had mysql user and group.

Explanation

• mysql was in the LDAP passwd and group from someone else in this large organization.

• Apparently the mysql-community-server rpm skipped creating mysql in the local /etc/passwd and /etc/group because mysql was in LDAP.

• During system initialization systemd-tmpfiles apparently runs before LDAP client starts.

• When systemd-tmpfiles ran, mysql user and group were unknown, as reported in /var/log/messages.

• Therefore systemd-tmpfiles did not create /var/run/mysqld.

Fix

• Create mysql in local /etc/passwd and /etc/group with user ID and group ID matching mysql in LDAP user and group.

• After this fix, mysql starts successfully during system initialization.