Can’t Create/Write to File ‘/var/log/mariadb/mariadb.log’ – Fixing MariaDB Logging Issues

loggingmariadb

I'm troubleshooting a MySQL no-start on CentOS 7 VM. It is a bit unusual to see this since we have not made any configuration changes. The manual start command was taken from systemd logging. The error is the age old:

# /usr/bin/mysqld_safe --basedir=/usr
181221 17:42:49 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
181221 17:42:49 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
/usr/bin/mysqld_safe_helper: Can't create/write to file '/var/log/mariadb/mariadb.log' (Errcode: 13)

According to Red Hat Bugzilla – Bug 1061045, mysql:mysql needs the appropriate permissions, which we seem to have:

[root@ftpit w]# ls -Al /var/log
total 52764
...
drwxrwx---  2 mysql mysql      4096 Aug 16 11:05 mariadb

And:

[root@ftpit w]# ls -Al /var/log/mariadb/
total 99852
-rw-rw---- 1 mysql mysql 102138776 Dec 21 17:16 mariadb.log

And:

[root@ftpit w]# grep mysql /etc/passwd
mysql:x:27:27:MariaDB Server:/var/lib/mysql:/sbin/nologin

I also tried g-w as shown in the bug report.

Where should I look next for this error? Or how do I fix it?

Best Answer

Is SELinux running in enforcing mode? Run sestatus to find out. If so, it should be logging to the /var/log/audit/ directory. You can do grep mysql /var/log/audit/* to see if there are any problems related to "mysql" i.e. MariaDB.

Also, the correct privileges and SELinux context for the log directory and files are:

# ls -ldZ /var/log/mariadb/ drwxr-x---. mysql mysql 
system_u:object_r:mysqld_log_t:s0 /var/log/mariadb/
# ls -ldZ /var/log/mariadb/mariadb.log
-rw-r-----. mysql mysql system_u:object_r:mysqld_log_t:s0 /var/log/mariadb/mariadb.log

For instructions on how to set the right SELinux context, refer to the documentation: What to Do if MariaDB Doesn't Start - SELinux and MariaDB Path Changes.

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